indian animal science journal

SUPPLEMENT ISSUEON

AQUATIC GENETIC RESOURCES

April 2010] PHYLOGEOGRAPHY AND EVOLUTIONARY ASPECTS OF INDIAN FISHES 9

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65ma and final structuring taking place 42 – 55 ma endingthe Tethys Strait across Northern India. India’s proximity toAfrica and Madagascar during the northward movementfacilitated faunal exchange. Briggs (2003b) terms the driftingIndian landmass as a “biotic ferry” and an “evolutionaryreservoir” for Gondwana groups. This suffices to explain thegenealogical patterns of groups with recent distribution inAfrica, Madagascar and India. Such a concept also suggeststhat lineages also colonized South and South-East Asia “outof India” (Karanth, 2006; McKenna, 1973). A significantgroup of fishes which needs detailed study for speciationare the Cichlids of India and Madagascar, while theircounterparts have diversified to several hundred species inthe great lakes of Africa. The species from India andMadagascar got separated from the African species about165m years ago followed by a split between India andMadagascar about 90ma. It will be necessary to have an indepth look at the molecular phylogeny of the Indian endemicCichlids, now known from only three species, Etroplussuratensis, E. maculatus and E. canarensis. A similar, buthitherto un-noticed group of fishes are the blind clariids ofKerala, India (Horaglanis krishnai and H alikunhii) andAfrica. These blind catfishes live in the subterranean aquifersand we have touched only the tip of the iceberg. A systematicstudy of this group is called for as I feel many more generaand species may await discovery. Molecular phylogenicstudies of blind clariids should throw open new vistas on theevolutionary history of Indian fishes.

In “Population, Species and Evolution”, Ernest Mayer(1963) opined that in allopatric model of populationdynamics, genetic drift accounts for a gradual divergence ofpopulation combined with selection during extended periodsof separation or isolation by physical barriers to gene flow.Palaeogeolological events in the past have played major rolesin the distribution, abundance and pockets of great speciesdiversity in South – East Asia. However, the role of physicalbarriers, (some of which may not exist today, or, may havebecome enhanced manifold times), in speciation are not wellunderstood. Eustatic movements of sea level would be onesuch barrier for freshwater fishes during the pluvial periodsof the Pliocene- Pleistocene.

Satpura Hypothesis: Our knowledge of the biogeographyof India, especially the Ichthyogeography was enhanced bythe work, zeal and efforts of Dr. Sunder Lal Hora (Fig. 1)who propounded the Satpura Hypothesis to explain thebiodiversity and Malayan affinities of the faunal and floralelements along the watersheds of the Western Ghats of SouthIndia, North East India, [two of the 34 biodiversity hot spotsin the world (Viswanath et al. 2007; Ponniah &Gopalakrishnan, 2000)] and the Malay Peninsula. In presentday parlance, it represents “into India” migration from thefocal area of Yunnan in China passing through N.E. India,the Garro gap and along the Narmada-Tapti watershedsdraining the Satpura mountain ranges and on to the Western

Ghats. Another lineage passed through the Irrawaddy Systemof Myanmar southwards to Malaysia, geological events andchanges in watershed drainage patterns aided suchmigrations. In my work on “Classification, zoogeographyand Evolution of cyprinoid families Homalopteridae andGastromyzonidae” (Silas, 1953a) I had occasion to study indetail the Malayan affinities of these fishes in relation tothose of the Western Ghats. A very interesting aspect wasthe connectivity of the Sundaland based on glacio-eustasismswhen river systems of Malaysia and Indonesian islands, westof the island of Bali, were linked. The Wallace line betweenBali and Lumbok islands separated the faunal and floralelements of the Sundaland from that of Papua New Guineaand Australia. Eustatic moments during the interglacialperiods resulted in the present day disposition of these landand river basins. A similar connection between Sri Lankaand South India could have existed at that time accountingfor the great similarities in the fish faunal elements of theWestern Ghats and Sri Lanka. With respect to freshwaterteleost species, the streams and rivers originating from theWestern Ghats and Sri Lanka are two of the few sites in theworld exhibiting high degree of endemism and exceptionalbiodiversity. More endemic fishes from the Western Ghatshave been recently reported by Ponniah and Gopalakrishnan(2000).

I recollect the late forties and early fifties as an excitingperiod when Hora could elicit multi-disciplinary interactionfrom geologists, palaeontologists, palaeobotanists,palaeogeographers, besides botanists, mammalologists,ornithologists, herpetologists, ichthyologists and scientistsfrom other disciplines to get together and discuss issuesrelating to his Hypothesis. Sad to say, the last fifty odd yearshave not witnessed any such inter-disciplinary concertedaction on biogeographical problems. It was a rare privilegefor four of us, A.G.K. Menon, K.C. Jayaraman, T.V.R. Pillaiand myself to be associated with Hora at this crucial time ofthe explosive growth of taxonomic and biogeographicinterest. My contributions were on the taxonomic assessmentand evolutionary divergences of the fishes with the so-calledMalayan affinities in Peninsular India (Silas, 1952) and alsoon insular speciation among the freshwater fishes of Ceylon(presently Sri Lanka) (Silas, 1953b). At that time we lackedgenetic tools to evaluate species diversity and intra-specificlevels of diversity. Two excellent and pioneering works byPillai (1951) on racial studies in Hilsa ilisha and Puntiussarana were mainly based on morphological and meristiccharacters. Probably the time is now appropriate to explicitlyreconsider some of the issues discussed on the influx ofspecies and speciation in time and space using geneticmarkers. It is in this context that genetics has an importantrole to play in the study of Indian biogeography.

Natural fish populations are declining at an alarming ratein many parts of the world due to over-fishing and other manmade activities. The very sustainability of fisheries resources

10 SILAS [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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are being affected and their gene pools and genetic diversitybeing eroded. Rapid advances in molecular biology havehelped to develop “molecular markers” in the form ofRestriction Fragment Length Polymorphism (RLFP) ofnuclear and mitochondrial DNA. In a milestone publicationentitled “Intraspecific phylogeography, the mitochondrialDNA Bridge between population genetics and systematics”,J.C. Avise and Colleagues (1987) proposed the term“Phylogeography” as a discipline involving biogeographyand population genetics. Phylogeography, by definition isthe use of tools of molecular biology, especially themitochondrial DNA (mtDNA) to infer phylogenetic historiesof taxa. It could help discern the evolutionary processes thatgenerate biodiversity. More recently, Bermingham andMoritz (1998) opined that comparative phylogeographicanalyses could permit detailed studies of “landscapeevolution, including the dispersal of fauna through a region,speciation, adaptive radiation and extinction” besides helpmolecular genetics for fisheries management andconservation, especially of threatened species.Phylogeographic reconstruction could show how specieshave originated by range expansion in time and space, andhas facilitated genealogical traces to be followed acrossgenetic boundaries between populations, species and highertaxonomic levels. With the advent of polymerase chainreaction (PCR), some quantitative changes in the approachof studying inter-population genetic variation gainedmomentum. The availability of nucleotide sequence data hashelped to develop universal oligonucleotide primers toamplify specific regions of mitochondrial DNA. TheRandomly Amplified Polymorphic DNA (RAPD) techniqueusing random oligonucleotide primers (Williams et al. 1990)became useful for stock identification studies. DNAfingerprinting by using minisatellites and especiallymicrosatellite markers provided finer resolution. Since theserepetitive DNA regions are not under the stringent controlof natural selection, they generally show higher level ofgenetic divergence at the nucleotide sequence level. Thesemarkers are useful in detecting the population and identifyingindividuals (Zardoya et al. 1996).

With the facilities, infrastructure and trained manpoweravailable with us today, I would call for a more intensivestudy of the biodiversity of our fishes in the wild as well ascommercially important species, whether in aquaculture orin capture fisheries, adopting a phylogeographic approach.This could conceptually bring about a new look of our speciesin the light of barcoding, aquaculture, green certification,trade and related aspects where precise nomenclaturebecomes essential. This cannot be done at a leisurely phaseas most of our freshwater, brackishwater and coastal aquaticecosystems are under ever increasing pressure fromanthropogenic activities. I would like to cite one goodexample of results of concerted action. As recent as 2002,over 100 species of Racophorine tree frogs were described

in Sri Lanka using mtDNA in combination withexophenotypic measures, when only 18 species werepreviously known. Many more could have become extinctthrough human activities (Megaskumbura et al. 2002). Thelast said is true for the Indian scenario as well. Let us notforget that any work on Phylogeography should have amultidisciplinary approach and knowledge of biogeography,ecology, behaviour and other aspects of the species orpopulation.

In the ocean environment though there appears fewphysical barriers and larval dispersal in general are extensive,yet, the tropical seas and ecosystems such as the coral reefsevince high species diversity which has puzzled thoseinvolved with allotropic species models. Studying the wrassesgenus Halichores, Rocha et al. (2005) found strong partitionbetween adjacent ecologically distinct habitats (in H. vittatusand the species pair H. radiatus/H. brasiliensis they observed3.4% and 2.3% divergence respectively) “but high geneticconnectivity between similar habitats separated by thousandsof kilometers.” According to them, “The concordance ofevolutionary partitions with habitat types, rather thanconventional biogeographical barriers, indicates parapatricecological speciation, in which adaptation to alternativeenvironmental conditions in adjacent locations overwhelmthe homogenizing effects of dispersal.” This probably solvesthe puzzle about the high biodiversity of coral reef fauna.Other recent studies also show the local retention of reeffish larvae (Jones et al. 1999; Swearer et al. 2002), activehabitat choice by larvae (Bierne et al. 2003) and reducedgene flow over short geographical distances (Taylor &Heilberg, 2003) indicating the possibilities that ecologicalpartitions can drive speciation, especially when contrastingenvironments are in geographically separated, but potentiallyconnected locations (parapatry) leading to high biodiversityin coral reefs.

Determining the status of a taxon: The status of a taxoncan be understood by surveying its range of distribution,abundance and population composition; and decision can betaken accordingly for its conservation management. The basicknowledge of its taxonomy, biogeography, life historycharacters such as age structure, fecundity, spawningbehavior and running time in the case of migratory speciesand straddling stocks will be of immense help. All theseinformation can be obtained from scientists, naturalists,conservationists and the folk who are the traditional users ofthe resource, and documented. The technical informationavailable on the structure of the population should becatalogued preferably by computerized data base for quickretrieval and exchange of information among the scientistsand the managers. The status of a taxon can be ascertainedbased on the above data base and conservation programmesdesigned accordingly.

Importance of stock identification: Stock identificationwill improve our understanding about the genetic structure


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of natural populations. The determination of genetic variationwithin and between populations can discriminate betweengenetically poor and rich population in terms ofheterozygosity and polymorphism. This information will helpto decide the best source of material for introduction orrehabilitating a threatened stock.

The stocks are believed to be locally adapted populations.Therefore, they should be treated as the unit of conservationand the management of endangered and commerciallyimportant taxa. Phylogeography could help a stock to belabeled to its geographical origin. This could help inunderstanding the migration pattern between populations anddeducing past events of colonization.

Hybrid identification and introgression detection:Significance of hybridization and introgression as a sourceof gene flow between taxa, especially at the intra-specificlevels involving sympatric subspecies and sibling speciesneed our attention. Finding out species specific molecularmarker is essential for identification of F1 and later generationhybrids. Morphological (morphometric and meristic)characters based on the assumption of phenotypicintermediacy in the hybrid to that of the paternal species havebeen traditionally used for F1 hybrid identification. Thesemorphological characters are most often not reliable forcorrect identification. Moreover, the later generation hybridscannot be detected by this method.

Chromosome number and structure analysis is anapproach. Chromosome studies have been used in the analysisof hybrid members of Salmonidae, Esocidae, Cyprinidae,and Cyprinodontidae. However, to identify the hybridbetween the species possessing identical chromosomenumber as in the case of Catla, Rohu and Mrigal with 2n =50, studying the chromosome morphology (the number ofmetacentric, submetacentric and telocentric chromosomesthat constitute the karyotype in a species) would be essential.Since chromosomes in fishes are small in size and classifyingthem by centromeric position is a subjective exercise, it wouldbe difficult to measure the chromosome arms accurately. Thechromosome information, therefore, is of limited use indetermining the hybrids. The fluorescence in situhybridization technique (FISH) is potentially a powerfultechnique that may find greater application in future tocharacterize the species and distinguish the F1 and F2 hybrids(Phillips and Reed, 1996).

Electrophoretic analysis of informative allozyme loci withfixed allelic differences between species can be analysed toidentify hybrids. By using six or more species specificunlinked isozyme gene loci, it is possible to discriminate F1and post-F1 fish hybrids accurately. Nuclear DNA RFLPshows biparental inheritance in a Mendelian fashion. Thismethod can be used for both species and hybrid identification.Mitochondrial DNA RFLP/sequence data of selected genessuch as 16S rRNA is useful in identifying the maternity ofthe hybrid in conjugation with nuclear DNA or isozyme

markers. Mitochondrial DNA can also be used for studyingthe direction of hybridization in natural populations anddetecting the occurrence of introgression. Inadvertenthybridization of Indian major carps has been detected inhatcheries using mitochondrial DNA RFLP (Padhi andMandal, 2000). Occurrence of hybrids in nature is notuncommon. I have the experience of dealing with anenigmatic specimen of tuna from off Mangalore whichapparently could be a hybrid between Euthynnus affinis andKatsuwonus pelamis but still doubt persists (Silas et al. 1981).In such cases molecular techniques may be highly useful.

Determining the genetic problems: To determine thegenetic problems, gene pool monitoring is essential. Havingprior knowledge about the status of a taxon and its geneticdiversity, the geneticist can determine the type of geneticproblems to resolve through development of soundmanagement strategies. The following questions may beaddressed to find out the genetic problems:

• Has population size reduced? If yes, the occurrence ofinbreeding and genetic drift is probable, which can beascertained by heterozygosity and polymorphismanalysis.

• Is inbreeding between different stocks going on due topurposeful introduction and inadvertent escapement?If yes, does genetic admixture lead to geneticcontamination?

• Does inter-specific hybridization occur between closelyrelated species? If yes, is genetic pollution occurringdue to genetic introgression?

• Does chemical pollution (at a lower dose) affect fishgene pool by causing genetic toxicity?

Conservation approaches: Once the goal and tasks ofconservation are decided, a specific management approachcan be designed. The genetic goal of a conservationprogramme is to conserve the genetic diversity, thoughinherently it is very complex. Hence, considering it ascomponents would be useful in conservation planning. Forthis it is essential to address three fundamental questions:What to conserve?, Where to conserve? and How toconserve? Let us look at this more critically:

What to Conserve?: Protecting an ecosystem may be amethod of conserving “everything”. This approach is broadbased, non-specific, cost effective and relatively simplistic.No special knowledge is required of the biology and geneticdiversity of a species for conservation management. Thismay be advantageous in view of our inadequate knowledgeof the genetic diversity and its potential or actual value.However, since the role of a particular species is ignored infavour of ecological process and community organization,this approach may prove ineffective, for the conservation ofan endangered species. Conservation may aim at a “specificspecies”. A species becomes prominent in conservationplanning for a number of reasons: i) when it is declining dueto anthropogenic stress in natural waters, ii) when it is crucial


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for the well being of its ecosystem, or iii) when it isendangered and chosen for recovery by special managementmeasures. To conserve a declining species, we should havesound knowledge about its biology, biogeography, andgenetic diversity. Without proper knowledge, inter-populationgenetic diversity cannot be conserved.

Where to conserve?: Conservation can be done in situ ina safe refuge or ex situ in the laboratory. In situ conservationmeans conserving the whole ecosystem or the totalcommunity in its natural location without any specificattention on any particular species. However, when a speciesis of special concern in situ conservation could proveinadequate. Habitat degradation could affect the reproductionof a species when ex situ conservation becomes an option.Developments in biotechnology have made it possible forcryopreservation of spermatozoa in sperm bank and workon embryo preservation is also being attempted. Thegermplasm can also be stored in the laboratory in the formof DNA Bank as i) total genomic DNA, ii) in the form ofDNA library ie., genomic DNA or cDNA library or iii) ascloned DNA fragments. This would also require properdocumentation, labeling and proper preservation andtechnical expertise to handle the same. Since the stored DNAmay be useful for the recovery of some genes and not thegenome as a whole, it may be helpful for research use, andcannot replace the natural genetic diversity.

How to conserve?: This may have two aspects, onemanaging declining population and the second, managingendangered species. For managing the declining populationsome corrective measures based on the following geneticprinciples may be an answer. i) the effective population sizeshould be maintained as large as possible to maximize thecontribution of a large number of adults for reproduction, ii)the causative factors that reduce the effective population sizeshould be controlled. If there is a genetic bottleneck, theduration should be reduced as far as practicable, and iii) thebarriers that create discontinuity in an inbreeding populationshould be disrupted to maintain continuity of gene flow. Forthis it will be necessary to protect the species and habitat insitu from anthropogenic stress, by actions such as, imposingban on fishing during breeding season, gear and mesh sizeregulation, and regulated well monitored fishing formaintaining the population size. In rivers, stretches may bedeclared as sanctuaries. To make this work, stakeholder andpublic participation will be essential. If the population densityis critically reduced, supportive breeding for conservationmanagement maybe necessary. But this would need a cautiousapproach as only a small fraction of the population is allowedto produce progeny for the next generation.

In the second, namely managing the endangered species,the population size being small, inbreeding and genetic driftare common genetic problems. Captive breeding is an usefulapproach for the conservation of endangered speciesfacilitating rapid growth of the population to enhance genetic

variability. Use of cryopreserved spermatozoa would be anuseful way for increasing the effective population size andrecovery of a severely endangered population. Tomoyuki etal. (2006) developed the first germ cell transplantation inlower vertebrates using fish PGCs and spermatogonia. “Infish germ cell transplantation system, donor cells aremicroinjected into the peritoneal cavities of newly hatchedembryos” allowing “the donor germ cells into migratetowards, and subsequently colonize, the recipient genitalridges. The recipient embryos have the immature immunesystems so the donor germ cells can survive and evendifferentiate into mature gamete their allogenic gonads,ultimately leading to the production of normal offspring”(underlining mine). “The results of the transplantation studiesin fish are improving our understanding the development ofgerm cell systems during vertebrate evolution”. This indicatesnew vistas open for multidisciplinary approaches in the filedof germ cells transplantation techniques, which the Bureaumay consider in its Vision.

Threats to fish genetic diversity: Habitat alterations dueto deleterious effects of pollution, damming of main rivers,siltation, introduction of non-indigenous species (exotics),networking and linking of river systems and waterways, allhave serious impact on native wild fish populations. Theextent and magnitude of such impacts needs to be geneticallyaddressed. Phylogeography could be the tool towardsconservation of endangered and threatened species.

Introduction of exotic species: “Exotic” is the term usedto indicate species living outside its natural geographicalrange. Terms such as “introduced”, “non-native”, “non-indigenous” “alien” or “invasive” are also used to denoteexotics. In aquaculture such introductions are for improvingproductivity or control undesirable aquatic organisms or forrecreational purposes. In many cases such instances haveproven disastrous. In India, the introduction of the commoncarp into Kashmir Valley has affected the indigenousSchizothoracinae fishes. In Gobindsagar Lake, theindigenous Catla catla was replaced by the exotic silver carp(Padhi and Mandal, 2000). Exotic ornamental fish such asthe green sword tail (Xiphophorus helleri), armoured catfishand African catfish Clarias gariepinus have been reportedfrom natural waters of Kerala. Sreenivasan (1995) reportedintroduction of non-native Chinese and Indian Major Carpsas the major factor leading to the decline of endemicPeninsular carps such as Cirrhinus cirrhosa, Labeo kontius,Puntius carnaticus, Puntius dubius and Puntius pulchellusin South Indian Reservoirs.

Stock introduction: To augment fish production inreservoirs and rivers, non-native/cultured stocks are oftentransplanted. The cultured stock which genetically differsfrom its wild relatives, may sometimes escape from pondsor cages into natural waters, creating an opportunity for inter-breeding between non-native/cultured stock and native/wildstock. We have not hitherto conducted impact studies of


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hatchery stocks or wild relatives, especially the impact ofhatchery reared Indian Major Carps. The genetic admixturedue to the un-thoughtful stock transfer from one region tothe other may also be detectable. Ignorance of the geneticpopulation structure may result in loss of genetic diversity,reducing productivity and damage to the ecology. Knowledgeof the size of the component population becomes essentialwhen we have to go back to the wild stock for replenishingbrood-stock for aquaculture.

Genetic impact of Introduction: The impact of introductionof exotics is a matter of concern because of ecological andgenetic reasons. Predation on native species or competitionand spreading of pathogens or parasites are some commonecological concerns. In short, genetic impacts could resultin reduction of ‘effective population size’ by the ecologicaland other effects of introduction and also alter or make extinctthe gene pools of the species/stocks by cross breeding/hybridization and backcrossing. In some cases, stock transferwhich initially appeared to be beneficial turned out to bebad in the long run. We have a lot to research to do in thisarea.

Future challenges• To study the phylogeography of the commercially

important teleosts and shellfishes with a view tounderstand distinct stock-structure of the followingspecies for appropriate management decisions.• Bombay duck (Harpadon nehereus) and Hilsa ilisha

from different populations.• Etroplus suratensis, E. canarensis & E. maculatus

– (the only Gondwanan teleost forms in the wholeIndia) – from Kerala, Sri Lanka & the introducedpopulations form East coasts of India

• Endemic species of the Western Ghats and NE: 1)Silurus wynaadensis (Kerala) & S. morehensis(Manipur); 2) Neolissochilus wynaadensis (Kerala)and N. hexagonolepis & N. spinulosus (N.E.) 3)Tetraodon travancoricus, Carinotetraodon imitator& Tetraodon cutcutia.

• Detailed Phylogeography of all the Mahseers ofIndia to be worked out.

• The lonely schizothoracid fish of the Western Ghats– Lepidopygopsis typus with other snow trouts ofHimalaya.

• Phylogeographic studies & species diversity offreshwater crustaceans – so far no reports from Indiaother than on M. rosenbergii. Another potentialspecies, Macrobrachium lar is found only inAndaman & Nicobar Islands - Comparing this stockfrom that from East of Wallace Line.

• The only true tuna in our coastal waters, Thunnustonggol which has very disjunct distribution, alongthe West Coast and Gulf of Mannar and in Australia.

Fragmentation and fusion of palaeo-drainage systems may

be an important factor generating current patterns of geneticand species diversity in hill-stream associated organisms. Wemay have to combine traditional, molecular-phylogenetic,multiple regression, nested clade and molecular demographicanalyses to investigate the relationship betweenphylogeographic variations and hydrological history ofdrainages in South India and North-East India.

DNA barcoding: Sequence information of selectedmitochondrial genes such as 16SrRNA, Cyt b and COI(chloroplast genes in plants) has been found extremely usefulin resolving taxonomic ambiguities and in describing neweukaryotic species. The last four years have seen a verysignificant development of “DNA barcoding” using COIsequence data for identifying species. This has great urgencyas many habitats are under great stress from anthropogenicactivities and there are estimates of the loss of severalthousands of species of organisms every year. This shouldcomplement conventional taxonomy and help us documentour aquatic (marine and freshwater) biodiversity and help inconservation management. In the production systems we aretoday looking at quality products in a value chain mode.Hence, traceability of fish and fish production becomes vital.DNA Barcoding can play a major role in preventing theadulteration of fishery products. I am glad that Dr. Lakra hastaken the lead in this mission oriented task and wish him andhis colleagues all success. However, as mtDNA is onlymaternally inherited, to avoid ambiguity, sequenceinformation of an ideal single copy nuclear gene such asRAG2 or Rhodopsin may also be used in addition to mtDNAfor species level identification.

Emphasis on marine sector: Phylogeography andphylogenetics of our coral reef, mangrove and sea grassecosystems and the fishes and invertebrates associated withthem are under pressure from manmade activities and naturalphenomena and climate change need special attention fordocumenting them. Genetic analysis using appropriatemarkers such as microsatellites could elucidate the geneticvariations in species at the intra-populations levels. Impropermanagement and misjudged priorities in the marine sectorhas resulted in the decline of major fisheries resources whichare replaced today by less value fish. We have hardly anygenetic information on species and at intra-specific levels toknow the extent to which populations and populationsegments have been wiped out or have reduced geneticdiversity within populations. Loss of genetic viabilityassociated with over-fishing of specific species in commercialoperations need investigation. Greater attention should bepaid on behavioral ecology, speciation and analysis of socialstructure of freshwater fish species.

“Phylogeography” of NBFGR: I wish to express my greatpleasure that during the last 25 years NBFGR has developedas an unique Institution devoted to research on fish geneticresources, probably the only one of its kind. This speaks alot about the Directors and staff who have helped to mould it


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as a Centre of Excellence in fish genetic research and I havesatisfaction in seeing the Bureau develop from strengthduring.

My memory goes back to the early 1980’s when I hadprepared a plan for the establishment of a Bureau of FishGenetic Resources at the Central Marine Fisheries ResearchInstitute, Cochin, Kerala and the Government had sanctionedRs.22.67 Lakhs for setting up the Bureau in the 6th Five YearPlan period as a Project with a Centre at CMFRI. The Bureauwas visualized as an agency to collect and collate informationregarding the genetic resources, particularly of culture andcommercial value. In perspective, the Bureau was to be thenucleus of a full fledged National Bureau to have anintegrated approach for the collection, conservation, andeventual utilization of genetic resources of finfishes,crustaceans such as shrimps, prawns, lobsters and other shellfishes of India. The Project was initiated with Late Dr. ArunJ. Jhingran as Project Director and this was followed by theappointment of Dr. P. Das as Director heading the Bureau atAllahabad (later shifted to its permanent campus at Lucknow)and with a research unit at CMFRI campus, Cochin. I washappy when one of my erstwhile colleagues, Dr. A. G.Ponniah succeeded Dr. P. Das as Director. Thanks to ICAR,I have also been associating with the Bureau as Chairman ofthe Research Advisory Committee during the last few years.The successive directors including Dr. W. S. Lakra and foran interim period Dr. D. Kapoor and the staff have allcontributed towards the growth and enhancing the vision ofthis great Institution.

Nevertheless, I must mention as an anecdote, theinternational reaction to the setting up of a Bureau of FishGenetic Resources in India. At the ACMRR Meetings withfishery experts at FAO, Rome in 1981 when I mentionedabout ICAR’s plan about setting up a Bureau of Fish GeneticResources as we already had a Bureau of Plant GeneticResources, the reaction was one of derision: “A bureau offish genetics!! In India??” “What was the need for India tohave a Bureau of Fish Genetics, unheard of in othercountries?” Looking back, we should all appreciate thecreative thinking and vision of ICAR which has made theBureau a reality. So the phylogeography of NBFGR -originated at Cochin, migrating northwards to Allahabad andthence to the North West to Lucknow! Today we see the seachange brought about by NBFGR and its achievement in theareas of its mandate.

I wish the institution all success in implementing its Vision2020 as well as take up creative and innovative research anddevote attention on core areas of its mandate. May the Bureaugrow from strength to excellence and see many more jubilees.

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Silas E G. 1953a. Classification, Zoogeography and Evolution ofthe fishes of the Cyrpinoid families Homalopteridae andGastromyzonidae. Rec. Indian Mus. 50 (2): 173–264.

Silas E G. 1953b. Speciation among the freshwater fishes of Ceylon.Pp. 248 – 259. In: Symposium on Organic Evolution; N.I.S.I,New Delhi.

Silas E G. 1956. Sunder Lal Hora. Copeia 2: 134–36 and Plate I.Silas E G, Pillai P P and Muthiah P. 1981. Euthynnus sp. or an

intergeneric hybrid of tuna: An enigma. J. Mar. Biol. Assn. India18 (3): 411–20.

Sreenivasan A. 1995. Where have all these fish species gone?Fishing Chimes 15 (2): 7–9.

Swearer S E, Shima J S, Hellberg M E, Thurrold S R, Jones G P,Robertson D R, Morgan S G, Selkoe K A, Ruiz G M and WarrenR R. 2002. Evidence of self recruitment in demersal marinepopulations. Bull. Mar. Sci. 70: 251–71.

Taylor M S and M E Hellberg. 2003. Genetic evidence for local

recruitment of Pelagic larvae in a Caribbean reef fish. Science299: 107–09.

Tomoyuki O, Ayaka Y, Nagasawa K, Shinya S, Kobayashi T,Takeuchi Y, Yoshizaki G and Yoshizaki G. 2006. Manipulationof Fish Germ Cell: Visualization, Cryopreservation andTransplantation. J. Reprod. Dev. 52 (6): 685–93.

Viswanath W, Lakra W S and Sarkar U K. 2007. Fishes of NorthEast India. NBFGR, Lucknow, I – XVIII, 1 – 264.

Warner R R. 1997. Evolutionary Ecology: How to reconcile pelagicdispersal with local adaptation. Coral Reefs 16: 5115–20.

Williams J G K, Kubelik A R, K J Livak, Reafalski J A and TingeyS V. 1990. DNA polymorphisms amplified by arbitrary primersare useful as genetic markers. Nucleic Acids Research, 18: 6531–35.

Zardoya R, Vollmer D M, Craddock C, Streelman J T, Karl S andMeyer A. 1996. Evolutionary conservation of microsatelliteflanking regions and their use in resolving the phylogeny ofcichlid fishes (Pisces: Perciformes), Proceedings of the RoyalSociety London, B 263: 1589–98.

Taxonomy is the science of finding, describing and namingorganisms, also known as alpha- taxonomy. This science issupported by institutions holding collections of theseorganisms, with relevant data, carefully curated in NaturalHistory Museums, Herbaria and Botanical Gardens. Toformulate effective and appropriate measures to protect andpreserve biodiversity, an accurate understanding of alpha-level taxonomy is very much essential (Kottelat, 1995).Alpha-taxonomy focuses more on the species end of thatspectrum, i.e., classifying organisms into species-groups, andclassifying those into genera, rather than determining thehigher-level relationships between families or orders. It isthe most elementary discipline and inclusive part of biology.Organisms cannot be discussed or treated in a scientific wayuntil some clarification of its taxonomic status has beenachieved. In other words it makes the diversity accessible toother biological disciplines and remains the basis for furtherstudy (Wilson, 2000).

Systematics, on the other hand, deals with the relationshipsbetween taxa, especially at the higher levels. It is the studyof the diversity of organisms and their relationships in orderto understand the evolutionary history of life. Biologicalclassification is based on systematic studies. It might seeman ivory-tower discipline which has nothing to do with thelives of ordinary people. The importance of taxonomy andsystematics lies not only in making the information ondiversity of organisms accessible to other biologicaldisciplines, but also in planning for their protection andconservation. Thus, both taxonomy and systematics have

their part in the protection of the environment. It was rightlypointed out by Nelson (1994) that systematists could play aleading role in protecting diversity.

Why taxonomy is neglected ?We may have some idea on why taxonomy is neglected

from Shunsuke’s (2005) report of his conversation with thefamous taxonomist, Ernst Mayer in October 1994. Whenasked why people think taxonomy as descriptive and not ascience, Mayer answered that in science, the facts first haveto be explored without which theories can not be put forward.In order to get facts, findings have to be described. So, thedescriptive stage is the beginning in everything or in everyscience. Mayer also puts the reason to the decline intaxonomy to be due to the immense biological diversity. Wehave millions and millions and millions of species. Workson basic cellular processes, say about how certain moleculesgo through membranes, it is applicable to a very vast realmof life. Thus, it will interest an enormous number of differentpeople. There is a great deal more glamour in working onthings that have a very wide application in biology. Ifsomebody works out the taxonomy of some rather obscuregenus of insects, it would be only of interest to the peoplewho are interested in that genus of insects.

Here, attention may be drawn to Rainboth’s (1996)statement: “correct species identification is the basic startingpoint for any type of biological study, particularly one onwild populations. For research on ecology and appliedecology, important components of fishery science, it isimportant that each name applies to only a single speciesand that each species is known by a single name”.

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[email protected]; [email protected]

Indian Journal of Animal Sciences 80 (4) (Suppl. 1): 16–25, April 2010

Emerging trends in taxonomy research and evolutionary systematics offish fauna of North-East India

W VISHWANATH1 and I LINTHOINGAMBI2

1,2Department of Life Sciences, Manipur University, Canchipur 795 003 Manipur

ABSTRACT

The importance of taxonomy and systematics lies not only in making the information on diversity of organismsaccessible, but also in planning for their conservation and sustainable use. Present taxonomy study involves understandingof inter-basin connections in the past, and drainage basin concept in case of freshwater fishes, tectonic setup of aparticular region. Naming and availability of species should strictly conform to the Code. Molecular approaches havebecome useful in phylogenetic analyses, but the real taxonomy should not be decimated. North-East India is rich in fishdiversity due to various factors. However, the diversity is still in the discovery survey state. Phylogenetic studies of thefishes with the prevailing concepts would come out with interesting results.

Key words: Basin, Fish, Morphology, Species, Taxonomy

April 2010] EMERGING TRENDS IN TAXONOMY RESEARCH AND EVOLUTIONARY SYSTEMATIES OF FISH FAUNA 17

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However, it is unfortunate that important taxonomicfindings during the course of phylogenetic analysis have beenforced by editorial policies of high impact journals either toignore their own taxonomic results or to treat them marginallyby including them in online appendices (Wiens et al. 2004).

Drainage basin conceptIn case of freshwater ecosystem, the present concept is

that fishes are distributed in a particular river basin unlessthese are introduced in other water bodies. Their congenersin an entirely separated different basin are now proved to bedifferent species. Various revisional studies of some specieswhich were regarded ‘highly variable and widely distributedforms’ have now been shown to be aggregates of distinct,often not even related species (Ferraris and Runge, 1999;Ng, 2003; Chakrabarty and Ng, 2005; Ng and Kottelat, 2000;Linthoingambi and Vishwanath, 2007; Vishwanath andLinthoingambi, 2007a, 2007b; Vishwanath and Darshan,2007). The affinity and interrelationships of species have beenrelated with longitudinal river valleys, inter-basinconnections, geological history etc.

The present fish fauna supports some of his conclusionsand contradicts others (Kottelat, 1989). Distribution of manygenera, viz. Osteobrama in Chindwin-Irrawaddy andSalween explains the concept. Various other evolution anddistribution of taxa and their phylogeny need extensive study.

Sampling sizeHundreds of species probably still await discovery for

obvious reasons, sampling of the habitats of rapids can bedifficult and dangerous, and they are under-sampled in mostcountries (Kottelat and Whitten, 1996). Many species wereconsidered to be widely distributed and the morphologicaldifferences between species of two different drainage systemswere once regarded as variable forms of one species.

Earlier fish taxonomy was often based on a limited samplesizes and poorly preserved specimens. Failing to interpretthe reason for observed variability: ontogenic, geographic,intra or interspecific; taxonomists conservatively concludedfor intraspecific variability (Ng and Kottelat, 2000).

The so called ‘catch-all cyprinid genus’ Puntius and thecatfish genus Glyptothorax which is referred to as ‘taxonomicwastebasket’ are suspected to be polyphyletic. The same iswith the catfish genus Akysis. This is because the species ofthese genera have been poorly studied due to their poorrepresentation in museum collections and their lack of marketvalue. The difficulty of using morphometric measurementsin diagnosing species of some genera is a problem that isencountered very often. The only solution to which wouldbe to examine a large series of specimens.

Type designationThe most appropriate thing to do in the light of all these

problems is to compare the holotypes of the nominal species.For some of the species whose holotypes were neverdesignated and whose original descriptions are rather subtle,it has become inevitable to designate a lectotype in order tostabilize their taxonomy, and serve stability and universalityto nomenclature, by referring to the International Code ofZoological Nomenclature (Code). For example when a caseof misidentification of species is involved, under Article 70.3of the Code, an author now has the option to select whichspecies is best suited as type species, either the speciesoriginally cited (Article 70.3.1) or the species actuallyinvolved but misidentified (Article 70.3.2).

The history of oriental fresh water ichthyology starts withHamilton’s (1822) work on the Fishes of the Ganges.However, Hamilton’s species create some difficulties tomodern ichthyologists as there are no types for any of them.Most descriptions are very short and many have noillustrations. Some authors claim that they are unidentifiable.

The descriptions of fishes by Gray (1830-1835) are basedon the drawings of Major General Hardwick’s drawings.

However, the code (1999) states that for every speciesand subspecies, a name bearing type (holotype, syntypes,

Fig 1. Subregions of fish fauna in Asia

The Asian fish fauna may be divided into three subregions(Fig. 1). 1. South Asian, consisting of Irrawaddy,Brahmaputra, Ganges and Indus basins and Peninsular India;2. South-East Asian-Mekong, Chao Phraya, Mae Khlongbasins, Malay Peninsula, S.E. Thailand to S.W. Kampuchiaand 3. East Asian-Red River, Nanpang-Jiang, Yangtze andTaiwan (Kottelat, 1989).

Inter-basin connectionsTo trace the evolutionary history of fishes in a drainage

basin, we need to understand the inter-basin connections ofthe past. At a time between post-Oligocene and present, theupper Irrawaddy was connected to the Sittang, the Tsangpoto the Chindwin and lower Irrawaddy and the upper Salweenwith Irrawaddy.

18 VISHWANATH AND LINTHOINGAMBI [Indian Journal of Animal Sciences 80 (4) (Suppl.1)

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lectotype or neotype should be fixed. For those taxaestablished before 2000, name bearing types should be fixedfrom the type series. If no name-bearing type is believed tobe extant, a neotype may be fixed (Art. 72.2). A proposal ofa new nominal species-group taxon after 1999 must includethe fixation of a holotype or syntypes (Art. 72.3).

Citation of Species names and role of the author’s namesThere has been a tendency for some taxonomists to credit

the authorship for a species different from the authorship ofthe whole paper. For example, in a paper authored by Singh,Sen, Banarescu and Nalbant (1982), there are descriptionsof two genera, viz. Mesonemacheilus and Physoschistura andtwo new species. The two generic names are followed byBanarescu and Nalbant, while one species, M.reticulofasciatus is followed by Singh and Banarescu andanother, P. elongata by Sen and Nalbant. Although the paperis authored by four workers, two each of them seem to beresponsible for the description. But, nowhere in the mainpaper, there is any mention that the particular genus or speciesare described by the authors whose names followed the newnames. In another case, there is a description of a new species,Sisor chennuah Ng and Lahkar in a paper authored by Ng(2003) who also did not mention the contributions of theworkers.

International Code of Zoological Nomenclature (the Code)(1999) in Article 50.1 states that the author of a name is theperson who first publishes it (Arts. 8, 11) in a way thatsatisfies the criteria of availability (Arts. 10 to 20). Article50.1.1 further states if it is clear from the contents thatsomeone other than the author of the work, is aloneresponsible for the name other than the actual publication,then the other person is the author of the name. If the identityof that other person is not explicit in the work itself, then theauthor is deemed to be the person who publishes the work.Thus, to avoid confusion and to keep in conformity of thecode, the contribution of the worker, other than the author ofthe publication has to be explained in the main text of thepublication itself.

Taxonomy provides opinions on species boundaries, andon the phylogenetic relationship between species. It providesa stable naming system that in today’s jargon is a portal to ahuge, if not always easy to access, store of information abouta species. It has become inevitable that easy access to museumspecimens and libraries to retrieve essential information bemade to all, without which it would democratize taxonomy.

Phantom taxonomyLack of complete taxonomic knowledge can lead to the

production of “phantom taxonomies”: those that first appearin online appendices as downloadable documents, in whichboth the new taxonomy and the authors are difficult to track.“Phantom nomina” (Vences et al. 1999) refers to new nominaaccidentally published in amateur publications without proper

descriptions and vouchers, while “phantom references” pointto references that were quoted as “in press” or “inpreparation” but were never published. Unreliable taxonomicinformation stemming from the need for rapid publication isequally unacceptable (Wheeler et al. 2004) given that, intaxonomy, unlike other disciplines, poor science cannot beignored (Giribet and Wheeler, 2007).

New Code (effective from 1.1.2000)The revised code which is effective from 1.1.2000 has

certain amendments, e.g., obligation to explicitly fix namebearing types for new species-group taxa, method of“publication” employing ink on paper or read-only laser disksdeposited in at least five major publicly accessible librariesnamed in the work itself. The following changes have beenmade:

1. A new name published after 1999 is available only ifindicated as being new: sp. nov. gen. nov or equivalentterms.

2. A new species-group nominal taxon must include thefixation for it of a name-bearing type (a holotype orexpressly indicated syntypes).

3. Name bearing preserved specimen/specimens,proposer include a statement naming the collection inwhich the name-bearing type is or will be deposited.

4. A new genus-group nominal taxon for trace fossils mustinclude the designation of type species.

5. If new family-group name is proposed, adopt genericname as the stem to avoid homonymy.

6. Lectotype designation- accompanied by a statementto the effect that the designation is made with thepurpose of clarifying the application of the name to ataxon.

7. In the event of rediscovering a lost holotype, syntypeor lectotype, designated neotype will be rejected.

8. If the existing name-bearing type of a species–grouptaxon is indeterminate, so that the correct applicationof the name to a particular taxon is doubtful (nomendubidum), an author should request the Commissionto set it aside and designate a neotype.

9. A work will be treated as published only if the durable,unaltered copies (i.e., on read-only laser disks) havebeen deposited in at least five major publicly accessiblelibraries named in the work itself.

10. For purposes of zoological nomenclature, the followingkinds of material are treated as unpublished:a. electronically distributed text or illustrationsb. downloaded copies or printouts of such materialc. abstracts of papers, posters, lectures, etc., issues to

participants at congress, symposia and othermeetings but not otherwise published.

d. Offprints distributed after 1999 in advance of thedate of publication specified in the work of whichthe offprint forms part.


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11. Not to displace a name which has been used as valid byat least 10 authors in 25 publications during last 50 years.

12. Maintain particular spelling, even if formed fromgrammatically incorrect stems.

13. If type species fixation is found based onmisidentification, a type actually involved may befixed.

14. Name used for higher group name, even if found laterthan the name of subordinate taxon, name is not to bedisplaced.

15. Commission is empowered to safeguard list of namesin major taxonomic fields.

Phylogeny (Greek: phylon = tribe and genesis = origin)Phylogeny is the evolutionary history of a species or group

of related species. Phylogeny is the study of the history: theorigin, the lines of evolution in a group of organisms andevolution of higher taxa. Traditionally, the phylogeneticstudies have been based on morphology, especially theskeleton, which is the only complete organ system availablefor detailed comparison with fossils (Greenwood et al., 1966).However, with availability of both primitive and advancedteleosts, approaches other than the morphological study maybe taken up for the investigation of their interrelationship.We should not imagine that, the full informational contentof the teleostean morphology has been extracted. It will takea long time to extract such informational content (Greenwoodet al. 1966). Osteological character provides valuable dataas it does not fluctuate physiologically, rhythmically orseasonally throughout the post-embryonic life of the fish(Jayaram and Anuradha, 2003).

Importance and the reliability of the osteological studyas a tool and basis for phylogenetic studies have been felt byvarious workers throughout the world. McClelland (1842)was a pioneer worker. Later Regan (1911); Greenwood etal. (1966); Roberts (1973); Kobayakawa (1992); Mo (1991);Bornbusch (1991); Chen and Lundberg (1995); Banarescuand Nalbant (1995); de Pinna (1996); and most recently Zhouand Zhou (2005) contributed in the subject.

Even within the realm of osteology, only a smallsuperficial portion has so far been accomplished. There areso many portions left to be studied. We doubt if more thanthe external anatomy of 95% of the species of living teleostshas been examined, and for many families, there has so farbeen little or no deeper study.

In India, the importance of osteology in fish taxonomyand phylogenetic research were also conceived by earlierIndian workers, viz. Bimachar (1933); Jayaram and Bimachar(1967); Mahajan (1966); Gauba (1966); Tilak (1963). Mostrecent osteology work is that of Shantakumar and Vishwanath(2006); Vishwanath and Shantakumar (2007).

Molecular approachThe increasing demand for phylogenetic patterns has

resulted in a sharp rise in molecular phylogenetic analysesand concomitant reduction in traditional taxonomic works.Although studies of phylogeny are commonly cited asevidence of active taxonomic research, ‘real’ taxonomy hasbeen decimated (Wheeler, 2004).

The value of molecular data in phylogenetic reconstructionis undeniable. Today, molecular markers are increasingly usedto study population differentiation, and most biologists cando this. Indeed, for any taxonomic issue with medical oreconomic consequences, it is inconceivable that moleculartechniques would not be applied. Similarly, biologists whomight have previously looked to taxonomists to provide aphylogeny of a group are finding it increasingly easy to do itthemselves as sequencing becomes cheaper and more widelyavailable. DNA sequence data play an essential role in thereconstruction of evolutionary relationships amongorganisms, resulting in insights in genetic affinities that mayconfirm or conflict with traditional taxonomy.

Taxonomists are often criticized for failing to act togetheras a community, not least in nature. However, the almostuniversal, voluntary adherence to the current codes ofnomenclature is arguably one of the strongest examples ofinternational scientific cooperation. The success of theInternational Commission for Zoological Nomenclature infacilitating this cooperation over many years makes it theright organization to spearhead a universal system for theregistration of zoological names. The commission appealsto all taxonomists to support this project and to engage inthe consultation needed to design the best system. We alsoappeal to all biologists, whose work depends on taxonomy,to throw their weight and influence behind this initiative.

These days systematics is greatly influenced by dataderived from DNA from nuclei, mitochondria andchloroplasts. This is sometimes known as molecularsystematics which is becoming increasingly more common,perhaps at the expense of traditional taxonomy (Wheeler,2004).

Evolutionary Systematics of Fish Fauna of North-East IndiaNorth-East India has as many as 296 fish species under

111 genera and 36 families (Vishwanath et al. 2007). Thefauna of the region is still in the discovery survey state andvery little work has been done on the evolutionarysystematics. Although fish exploration started with the workof Hamilton (1822) and continued upto 1940’s by Dr S.L.Hora and his team, there has been a long gap in the work.Only in late 80’s, the study started again. With theimplementation of United States Science Foundation fundedAll Catfish Species Inventory project, involving manyscientists around the world in 2003, scientists from outsidethe country have also explored catfishes from North EastIndia. Active inventory of ornamental fishes are also inprogress.

Before we proceed to evolutionary systematics, we must


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be aware of the various factors responsible for the presentfish distribution in the region.

Plate tectonics and Fish phylogenyPlate tectonics and fish phylogeny are two fields of very

active researches in which major new hypotheses can stillbe expected at any time (Kottelat, 1989). We are onlybeginning to understand the complexity of the evolution ofthe continents and all proposed phylogenies are likely tosuffer modifications. Ibotombi (1993) wrote that rifting andstretching of the crustal layer (lithosphere) of the presentManipur, possibly initiated sometime towards the close ofMesozoic era (upper cretaceous). The Manipur valley wasprobably evolved as a result of the passive rifting of thecontinental margins, i.e., sinking of a former plateau. Thusit is probable that the present Imphal river (Chindwindrainage) has a reverse course and it probably joined theBarak (Brahmaputra drainage) resulting in the presentdistribution of fish species common to both the systems.

Hora (1949) put forward ‘Satpura hypothesis’ to explainthe dispersal of specialized fishes evolved in the mountainsof Yunnan and Indo-China to Peninsular India. Thehypothesis is based on the concept of Darlington (1957) thatSouth-East Asia is ‘centre of origin’ of Ostariophysi. BothSatpura hypothesis and centre of origin theory have beennegated as there is no geological support. Both were basedon the the concept of continental stability. The presentconcept is that continents do move. Beaufort (1951) and Mani(1974) considered the disjunction pattern of distribution offishes of North-East India and South India as the remnantsof an older wider distribution and not of recent origin. Thisdisjunction is probably due to the extinction due to theCretaceous to Eocene Deccan volcanism (Sarasin, 1910).

Plate reconstructions (Fig. 2) based on palaeomagneticdata suggest that the Indian plate attained a very high speed(18–20 cm yr-1 during the late Cretaceous period) subsequentto its breakup from Gondwanaland, and then slowed to~5 cm yr-1 after the continental collision with Asia 50 myrago. The Australian and African plates moved comparativelyless distance and at much lower speeds while Antarcticaremained almost stationary. This mobility makes India uniqueamong the fragments of Gondwanaland. Thickness of thelithospheric root was important in determining their speed.Shear-wave receiver function technique revealed that whileother plates had thicknesses of 180–300 km, Indianlithosphere was only about 100 km thick. Thus, it resulted infastest movement and the resultant Himalayan orogeny(Kumar et al. 2007).

Reasons for DiversityThe region has rich fish diversity. The diversity is

attributed to many reasons, viz. the geomorphology,consisting of hills, plateaus and valleys, resulting in theoccurrence of a variety of torrential hill streams, rivers, lakes

and swamps; the drainage pattern which include the Ganga-Brahmaputra, Koladyne and Chindwin-Irrawady systems.Another important factor is the tectonic setting in the Indo-China subregion caused by collision of Indian, Chinese andBurmese plates, resulting in the formation of the mightyHimalayas and Indo-Burman ranges.

North East India forms part of two of the 34 biodiversityhotspots listed by Conservation International, they are: theHimalaya and Indo-Burma (Roach, 2005). The Himalaya isthe home of the world’s highest mountains and deepestgorges. The mountains rise abruptly, resulting in a diversityof ecosystems. The Indo-Burma, also called Indochinabioregion includes portions from eastern India to Vietnam.The whole of Arunachal Pradesh and Assam, north of theBrahmaputra, and Sikkim belongs to the Himalaya whileMizoram, Assam south of the Brahmaputra, Meghalaya,Nagaland and Manipur belong to the Indo-Burma. Kottelatand Whitten’s (1996) map of freshwater biodiversity hotspotalso covers areas of NE India.

The available data on the fishes of North East India is farfrom complete. This was due to lack of extensive surveywork in this area, particularly in the interiors of hills becauseof difficult topography, inaccessibility and lack of properlanguage communication. In the past few years, researchersin the region have made extensive surveys of the water bodiesand have added more species names to the list of fishes andadded a new dimension on the fish study. Changes have takenplace in the nomenclature, concepts of taxa and scheme ofclassification of fishes. With the publication of the result ofextensive surveys of fishes in the Indo-Chinese region, greatchanges have also taken place in the concept of the originand evolution of freshwater fishes of the region. Thus,students and researchers find difficulty in consulting bookson fish fauna published long ago.

History of IchthyologySince the pioneering work of Hamilton (1822), about 70

research papers have been published and as many as 139species of fishes have been described new from the region.

Fish genera endemic to the region

Fig 2. Tectonic set-up of continents 220 MY ago


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The Indochina bioregion including North East India ischaracteristic in having certain endemic genera of fishes, viz.Aborichthys Chaudhuri, Akysis Blyth, Amblyceps Blyth,Badis Hamilton, Bangana Hamilton, Chaca Gray,Chaudhuria Annandale, Conta Hora, Erethistes Muller andTroschel, Erethistoides Hora, Exostoma Blyth, MeyersglanisHora and Silas, Olyra McClelland, Parachiloglanis Wu,Pareuchiloglanis Regan, Pseudecheneis Blyth,Pseudoexostoma Chu, Pseudolaguvia Misra, PsilorhynchusMcClelland and Semiplotus Bleeker, Sisor Hamilton.

Advanced Fish TaxonomyFish systematics has taken a new turn with the

understanding of plate tectonics and continental drift andrejection of the theory of continental stability. Ichthyologistshave been looking into the geographical history, river basinformations and early fossil appearances for correlation withthe origin of fish and their evolution in time and space. With

the new concept, scientists are concerned in detailedinventory, cataloguing and conservation of fish germplasm.

Early workers had access to a very few and poorlypreserved specimens. With the new concept, various workers(Kottelat, 1996; Kottelat and Lim, 1993, 1995; Ng andDodson, 1999; Ng and Kottelat, 2000) re-examined ‘highlyvariable’ widely distributed species and concluded that theywere in fact aggregates of distinct, often not even closelyrelated species.

Many other species have emerged new in this way, viz.Gagata gasauyuh (Roberts and Ferraris, 1998), Badischittagongis, B. ferrarisi and B. kanabos, Mystus falcarius(Chakraborty and Ng, 2005), Sisor chennuah (Ng and Lahkar,2003), Pseudolaguvia ferula (Ng, 2005a), P. inornata and P.muricata (Ng, 2005a), Gogangra laevis (Ng, 2005b), Batasiospilurus (Ng, 2006), Pseudecheneis crassicauda and P.serracula (Ng and Edds, 2005), Amblyceps arunachalensis andA. apangi (Nath and Dey, 1986), Psilorhynchoides

1822 F. Hamilton (17)1835 J.E. Gray (1)1839 J. McClleland (5)1842 J. McClleland (8)1845 J. McClleland (1)1849 J. Muller and F.H.Troschel (1)1867 R.L. Playfair (1)1912 B.L. Chaudhuri (3)1913 B.L. Chaudhuri (3)1921 S.L. Hora (9)1923 S.L. Hora (1)1925 S.L. Hora (1)1935 Hora and Mukerji (1)

S.L. Hora (1)A.G.K. Menon (1)

1936 S.L. Hora (1)1937 E. Ahl (1)1950 S.L. Hora (1)1954 A.G.K. Menon (1)1966 K.C. Jayaram (1)1968 P. Bararescu and T. Nalbant (1)1972 G.M. Yazdani (1)1975 G.M. Yazdani and Talukdar (1)1982 A. Singh and P. Banarescu (1)

N. Sen and T. Nalbant (1)1984 R.P. Barman (1)1986 W. Vishwanath and H. Tombi (1)1987 A.G.K. Menon (6)

A.K. Datta, RP Barman and KC Jayaram (1)1988 L. Arunkumar (2)

W. Vish and Ch. Sarojnalini (1)1989 P. Nath and S.C. Dey (2)1990 W. Vish and K. Nebeshwar (1)

1991 J. Vierke (1)1993 W. Vishwanath (1)1994 N. Sen and B.K. Biswas (1)1995 W. Vish. and W. Manojkumar (1)1998 L. Kosygin and W. Vish. (1)2000 L. Arunkumar (6)2000 P. Musikasinthorn (1)

W. Vishwanath and Kosygin (2)Menon, Rema Devi and Vish. (1)

2001 K. Selim and W. Vsh. (1)2002 S. Kullander and R. Britz (3)

W. Vishwanath, Manojkumar and Selim (2)2004 W. Vishwanath and L. Juliana (4)

W. Vishwanath and K. Shanta (2)W. Vishwanath and K. Nebeshwar (1)Ng and Lahkar (1)H.H. Ng and D.R. Edds (1)

2005 H.H. Ng and Edds (2)H.H. Ng (4)W. Vishwanath and M. Shantakr (1)W. Vishwanath and K. Nebeshwar (1)

2006 H.H. Ng (4)W. Vishwanath and A. Darshan (1)W. Vishwanath and K. Nebeshwar (1)

1999 L. Arunkumar (1)W. Vishwanath and L. Kosygin (1)

2005 H.H. Ng (1)W. Vishwanath and I. Linthoingambi (1)W. Vishwanath and H. Joyshree (1)W. Vishwanath and K. Shanta (1)W. Vishwanath and A. Darshan (1)

2007 W. Vishwanath and I. Linthoingambi (7)W. Vishwanath and H. Joyshree (1)W. Vishwanath and A. Darshan (2)K. Nebeshwar, K. Bagra and D.N. Das (1)M. Kottelat et al. (1)

Year Worker No of sp. described Year Worker No of sp. described


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1822 Bangana dero, Batasio batasio, B. tengana, Channabarca, Crossochilus latius, Conta conta, Erethistes hara,Eutropichthys vacha, Labeo boga, Labeo pangusia,Nangra nagra, Ompok pabo, Pimelodus rama, Puntiusguganio, Raiamas bola, Securicula gora, Schisturasavona

1835 Balitora brucei

1839 Acanthocobitis pavonaceous, Garra nasuta, Labeodyocheilus, Neolissochilus hexagonolepis, Semiplotussemiplotus

1842 Exostoma labiatum, Garra annandalei, G. kempi, G.naganensis, Glyptothorax lissorhynchus, G. striatus,Olyra longicauda, Pseudochenies sulcata

1845 Poropuntius clavatus

1849 Erethistes pussilus

1867 Channa stewartii

1912 Danio naganensis, Olyra kempi, Schistura manipurensis

1913 Aborichthys kempi, Moringua hodgartii, Mystusdibrugarensis

1921 Aborichthys elongatus, Barilius dogarsinghi, Devarioacuticephala, Garra abhoyai, Lepidocephalichthysirrorata, Pseudolaguvia shawi, Schisturakangjupkhulensis, S. prashadi, S. sikmaiensis

1923 Parachiloglanis hodgarti

1925 Aborichthys garoensis

1935 Psilorhynchus homaloptera, Schistura devdevi,Schistura inglishi

1936 Crossocheilus burmanicus

1937 Badis assamensis

1950 Erethistoides montana

1954 Glyptothorax manipurensis

1966 Pareuchiloglanis kamengensis

1968 Neoeucirrhichthys maydelli

1972 Chaudhuria indica

1975 Puntius shalynius

1982 Mesonoemacheilus reticulofasciatus, Physoschisturaelongata

1984 Aborichthys tikaderi

1986 Puntius jayarami

1987 Schistura arunachalensis, S. nagaensis, S. sijuensis,S. singhi, S. tirapensis, Neonoemacheilus assamensis,Pterocryptis indica

1988 Danio yuensis, Garra manipurensis , Puntiusmorehensis

1989 Amblyceps apangi, A.arunachalensis

1990 Schistura chindwinica

1991 Channa bleheri

1993 Garra litanensis

1994 Nangra assamensis

1995 Psilorhynchus microphthalmus

1998 Garra compressus

1999 Homaloptera manipurensis, Myersglanis jayarami

2000 Akysis manipuirensis, Barilius lairoukensis, Channaaurantimaculata, Chela khujairokensis, Erethistesserratus, Garra elongata , Lepidocephalichthysmanipurensis , Macrognathus morehensis,Neonoemacheilus morehensis, Puntius manipurensis

2001 Aspidoparia ukhrulensis

2002 Badis kanabos, B. blosyrus, B. ferrarisi, Bariluschatrickensis, B. ngawa

2004 Acantopsis multistigmatus, Badis tuivaiei, Batasiomacronotus, Puntius bizonatus, P. ornatus, Rasboraornatus , Schistura khugae, S. reticulata, Sisorchennuah

2005 Erethistoides sicula, Garra nambulica, G.paralissorhynchus, Glyptothorax ventrolineatus, Sisorbarakensis, Pseudecheneis crassicauida, P. serracula,Pseudolaguvia ferrula, P. foveolata, P. inornata, P.muricata, Schistura minutus, S. tigrinum

2006 Batasio fasciolotus , B. niger, B. spilurus,Pseudolaguvia ferula, Pterocryptis barakensis

2007 Exostoma barakensis, Glyptothorax chindwinica, G.granula, G. ngapang , Puntius ater , P. khugae,Pseudocheneis sirenica, P. ukhrulensis, Schisturapapulifera, Psilorhynchoides arunachalensis

List of fishes (valid names) described from North-East India

Year Species Year Species


23

arunachalensis (Nebeshwar et al. 2007), Pseudecheneissirenica and P. ukhrulensis (Vishwanath and Darshan, 2007),Puntius ater and P. khugae (Linthoingambi and Vishwanath,2007).

In view of the rich fish diversity in the region and theirneed for categorization under IUCN threat criteria andconservation and to study their phylogeny, we need sincereefforts of scientists who know fish taxonomy. Detailedinventory, correct identification and naming and systematicstudy using traditional techniques supported by modern toolswill solve various problems in fish evolutionary systematicof North-East India.

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1College of Fisheries, Central Agricultural University,Lembucherra 799 210, Tripura

2 Department of Zoology, H.N.B. Garhwal University, Srinagar246 174, Uttarakhand

3Coorg Wildlife Society, Mercara, Karnataka


Mahseers in India: A review with focus on conservation and management

K DINESH, NANDEESHA M C1, NAUTIYAL P2 and AIYAPPA P3

College of Fisheries, Kerala Agricultural University, P.O. Panangad , Kerala 682 506

ABSTRACT

Mahseers inhabit the rivers and freshwater lakes of South and Southeast Asian countries. In India, the group is welldistributed right from the Himalayas up to the rivers of the Western Ghats. Most of the species belong to the genus Tor.Owing to their excellent sporting quality, the mahseers have been variously called as the ‘king’, ‘lion’, ‘tiger’, ‘the greatfighter’, etc., by the anglers. In certain parts of the country, it has also been even given the status of a ‘divine fish’. Dueto the similarities in the morphometrics and meristics, difficulties have been encountered in the correct identification ofthis group of fishes and recently molecular techniques have been used to resolve such ambiguities. To the local fisherfolk and the tribal people residing along the up-streams of rivers, mahseers have been of considerable importance asthey contribute much to their livelihood as well as food security. Despite their abundance at one time, mahseers aredeclining rapidly in different parts of India making them a ‘threatened’ group. Breeding technology has helped inundertaking conservation programmes of the Himalayan mahseer (Tor putitora) and the Deccan mahseer (Tor khudree).Efforts have also been made to understand the nutritional requirements of these species and to culture these speciesalong with other carps. Though the conventional farming of this fish is not promising because of the slow growthcompared to the Indian and Chinese carps, however, by formulating practical diets and appropriate technologies there isscope to harness the potential of this group of fishes. The culture of mahseers has to be undertaken with a multifacetedapproach considering their value in sport, food and aim at their conservation and scientific management. The involvementof the private sector like Tata Power Company Ltd., in the conservation of the mahseer has shown that long termcommitment can bring desirable outputs. The Coorg Wildlife Society is also trying for the management of the group bypromoting the ‘ecosystem based fish habitat conservation’. These examples clearly demonstrate the involvement of theprivate and public sectors with the peoples’ participation would provide the much needed support to protect this importantgroup of fishes. In this review, an effort is made to assess the progress on various aspects of taxonomy, biology, nutrition,reproduction, aquaculture and conservation of mahseers. The opportunities available to improve the livelihood of peopleby increasing the research and development efforts on this group of fishes and its tourism potential are also discussed.

Key words: Aquaculture, Conservation, Food and feeding, Mahseer, Management,Molecular markers, Taxonomy, Tor

Indian Mahseers, the big scaled carps have been anexcellent sport fish and attraction to anglers as well asnaturalists from all over the world since the nineteenthcentury. Langer et al. (2001) while compiling thebibliography of mahseers of the Indian sub-continentdescribed this group as the ‘King of Indian aquatic systems’.The mahseers are not only well known sport and food fish,but they are also our national heritage (Oliver et al. 2007).They are generally known to prefer cold, clear and swiftflowing waters with stony, pebbly or rocky bottoms andintermittent deep pools (Dinesh et al. 2008). Several authorshave observed that mahseer is declining in different parts of

India owing to the indiscriminate fishing of bloodstock andjuveniles, fast degradation of aquatic ecosystems,construction of dams, barrages and weirs and otheranthropogenic interventions/intrusions (Sehgal, 1992;Tandon et al. 1992; Bhatt et al. 1998a; Nautiyal et al. 1998;2007; Kumar, 2000; Menon et al. 2000; Ogale, 2002a; 2002b;Chalkoo et al. 2007; Dinesh and Nandeesha, 2007; Vinod etal. 2007; Oliver et al. 2007; Kalita et al. 2007). Because ofthe decline in the fishery, all the Indian mahseers have beenlisted as ‘threatened’ (Oliver et al. 2007). Mahseer is reportedto be present generally in the Tor zone (600–1200 m) of theglacier-fed Himalayan rivers (Singh and Kumar, 2000) withmuch more extended distribution to the lower reaches in thepeninsular Indian rivers (Ajithkumar et al. 1999). However,Bhatt et al. (1998a; 1998b) observed Himalayan mahseerfrom 273 m near Hardwar (29o52’ N; 78o10’ E) in the Gangato 560 m at Banghat (29o57’ N; 78o45’ E) in the Nayar.

April 2010] MAHSEERS IN INDIA 27

27

Surprisingly, in Kashmir , it is even reported from an altitudeof 1800 m from asl (32o17’ to 36o58’ N, - Prof. M. Balkhi,Agricultural University, Srinagar, Kashmir- pers. comm.).Raina et al.(1999) reported that they have the capacity tomigrate upto an altitude of 2000 m from asl during southwest monsoon. Jhingran and Sehgal (1978) reported that itis the index of thermal tolerance of the group which doesmatter during their migration and they avoid low temperature-areas, whereas, Nautiyal (2002) attributed the triphasedmigration of the group as an evolutionary response towardsefficient utilisation of the food resources in the habitats. Whilethe adults or prospective brooders may migrate 3-4 monthsin advance of the spawning season because of the hominginstinct and for priming themselves before reproduction, thejuveniles and adolescents seem to accompany them as partof the ‘learning migration’.

Undeniably, mahseer is one of the fiercest fightingfreshwater game fishes that exists in India with unparalleledstrength and endurance (Dhillon, 2004) and so this is theonly one word, fighting about and fighting against (Thapa,1994). It was the Oriental Sporting Magazine whichmentioned mahseer for the first time as an angling fish in1833. Lacy and Cretin (1905) referred the game as ‘playinga mahseer’. The book, ‘With Gun and Rod in India’ publishedby the Indian Government in 1958, described mahseer as anever fascinating lure to the hunter. ‘Circumventing theMahseer and other sporting fish in India and Burma’ (MacDonald, 1948) could be considered as the best treatise ofIndian mahseer in every respect. Hora (1951) deliberatedthe indigenous knowledge that existed about this fish. TheGolden Mahseer (biggest among the group) has been knownto reach 2.75 m (9 ft) in length and 54 kg (118 lb) in weight(Talwar and Jhingran, 1991). A maximum length of 274 cmwas reported by Hamilton (1822) earlier. A female measuring148.0 cm from the Saryu River, Kumaon Himalaya is theonly report available over the last two decades. A size of137.5 cm was reported in early eighties (Nautiyal and Lal,1981). Maximum weight reported for Tor mussullah and Torkhudree is 90 kg and 22.5 kg respectively (Gupta and Gupta,

2006). A female specimen of Tor khudree with a weight of19.5 kg and TL of 99 cm was collected in 2006 from Kerala(Dinesh et al. 2008).

TaxonomyTaxonomic uncertainity still remain in the identification

of mahseers especially while the morphological charactersare looked into. Many authors have critically analyzed andexplained the systematic position of the various species fallunder the Genus Tor and allied genera (Gray, 1834; Day,1873; 1878; Hora and Mukherji, 1936; Misra, 1959) andmany species/sub species got either included or excluded;no wonder, contradictory observations and explanations havealso been reported (David, 1953; Menon,1992; CAMP, 1998;Jayaram, 1997; Jayaram, 1999; Mirza and Bhatti,1996;Gopalakrishnan and Basheer, 2000). Desai (2003) stated thatthe carps with big scales, fleshy lips continuous at the anglesof the mouth with uninterrupted fold or groove across thelower jaw, two pairs of big barbels, lateral line scales rangingfrom 22 to 28 and length of head equal to or greater than thedepth of the body are considered as ‘true mahseers’ and areincluded in the genus Tor. CAMP (1998) workshop onFreshwater fishes of India organized with the objective ofassessing the status of freshwater fishes of the country haslisted eight species of mahseer, Tor khudree, Tor khudreemalabaricus (Jerdon), Tor kulkarni, Tor mosal, Tormussullah, Tor progenius, Tor putitora and Tor tor. Talwarand Jhingran (1991) described eight species of mahseercommonly found in India of which seven belonging to thegenus Tor; T. putitora,T. tor, T. mosal, T. khudree, T.mussullah, T. (Barbus) neilli (Day) and T. progeneius andone belonging to the genus, Neolissocheilus, N.hexagonolepis (the Chocolate mahseer). A tentative list ofspecies with their identification characters and geographicdistribution is presented in the Table 1. (adopted from Sehgalet al.2007 with other inclusions).

The species/sub species like T. mosal, T. neilli, Naziritorcheylinoides, T. moyarensis, T. kulkarni, T. malabaricus andT. remadeviae (Kurup and Radhakrishnan, 2007) are not

Table 1. Tor species reported from India

No. Valid Species Characters Distribution

1 T. putitora (Hamilton)-Golden/Putitor/ Head-pointed; HL > Complete HimalayasYellow fin/Himalayan mahseer Depth; LL: 23-28

2 T. tor (Hamilton)-Deep bodied/Red fin/ HL < Depth; LL: 23-28 Himalayas and NarmadaTuria mahseer

3 T. khudree (Sykes)-Deccan mahseer HL = Depth; fins bluish grey; Orissa and Peninsular India south of TaptiLL: 24-26

4 T. mussullah (Sykes)-Hump- HL < Depth; LL:24-27 Peninsular India - Krishna and Godavaribacked mahseer

5 T. progenieus (McClelland)- HL = Depth; LL:27-31 Eastern HimalayaJungha mahseer

Note : HL – Head length; LL- Lateral line

28 DINESH ET AL. [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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included as their taxonomic status is yet to be confirmed.NBFGR developed a number of genetic markers anddetermined genetic variations not only among differentspecies but also within the population of the same species ofmahseers. The chromosomal banding techniques or NOR(Nucleolar Organizer Region- cytogenetic method) have beendeveloped for different endangered and commercial speciesincluding T. putitora. Mohindra et al. (2004) have identifiedmicrosatellite loci in T. putitora and the loci were found tobe suitable for genetic diversity analysis. Lakra (1996)reported karyotypes of three species of mahseers, T. putitora,T. tor and T. khudree. Interestingly, apparent differences inkaryotypes and NOR band have been observed even in theclosely related species like T. khudree and T. mussullah(Anon., 2001a; Anon., 2001b). A comprehensive work,linking the traditional and molecular taxonomy, is suggestedto resolve the problem of taxonomic ambiguity. The attemptby Silas et al. (2005) to find out specific identity of T. khudreemalabaricus described by Jerdon (1848) by using RandomAmplified Polymorphic DNA (RAPD) markers is worthmentioning. This is the first report on the application ofRAPD technique for identification of a Tor species from theWestern Ghats (Silas et al. op. cit). Further, Silas et al. (2009)confirmed the taxonomical status of Tor malabaricus bycomparing the mitochondrial DNA of the species with thatof Tor khudree.

Food and feedingValuable and pioneering information on the biological

aspects of mahseer are available from the observations ofthe anglers. MacDonald (1948) noted that mahseer is anintermittent feeder. Green filamentous algae and other waterplants, slimy matter encrusted on rocks, insect larvae, etc.,have been recorded from the stomach contents of the Putitormahseer. Thomas (1897) observed aquatic weeds of all sorts,seed of Vateria indica or dhup of the west coast; bambooseeds, rice, paddy, crabs, small fish, earth worms, waterbeetles, grasshoppers, small flies, water or stone crickets,shrimps, molluscs or freshwater snails etc. in the gut of thefish. Karamchandani et al. (1967) and Desai (1982) reportedthe same feeding habit for mahseer with more vegetativepreference. Pisolkar and Karamchandani (1981) alsoindicated that macrovegetation forms the major part and theanimal matter forms the subsidiary portion in their gut.

The diet of T. putitora is reported to be diverse in differentriver systems. In the Ganga river system, the diet of thespecies comprised of insect nymph (Ephemeroptera,Plecoptera, Odonata), insect larvae (Trichoptera, Diptera,Coleoptera, Lepidoptera), miscellaneous insects, fish,organic debris, zooplankton, macrophytes, diatoms, otheralgae and sand. Nautiyal and Lal (1984) made observationson the feeding habits of the Himalayan mahseer migrants inthe Alaknanda and juveniles from the nurseries andcategorized them as marginal-cum-column feeders. The

adults which are more powerful swimmers definitely feed inthe column with insectivorous feeding habit as no other groupof animal was found in their guts (barring 1.6% fish that tooin the migrant adults only) which makes them to be rightlycalled as ‘monophagic’. Kishore et al. (1998) studied thedietary habits of the Gangetic Putitora and confirmed theircarnivorous habit. Variation in the dietary habits wasobserved in the early larval stages, 1–7 mm was omnivorousand 7–10 mm was carni-omnivorous. There were nodifferences between the two sexes with respect to diet. Adefinite shift from omnivorous/herbi-omnivorous tocarnivorous is reported to occur in fish attaining 7 cm sizewhich prove that it is the size that influences change in foodhabit. However, fish of 1+, 2+ and 5 + years of age arereported to become carnivorous, carni-omnivorous andomnivorous respectively. During migration, fish of all ageremain carni-omnivorous. Observations on the intraspecificcompetition in T. putitora stock revealed positive preference/selection for all insect groups, while negative for diatoms.Insects can be categorised as the ‘most preferred’ food itemof T. putitora owing to high values of Strauss Linear Index.The food spectrum is found to vary according to age, riversystems and habitat. The rate of feeding in golden mahseervaried according to the season and this is evident from thestudies of Mohan (2000) in Kumaon region of Uttarakhand.The rate was higher during winter and slowed down towardsthe monsoon. The estimation of Gastro Somatic Index alsosupported this observation. The fish was found to be fedmainly on the microbenthic biota available over the riversubstratum. Diatoms formed the most preferred foodcomponent supported by green algae, blue green algae andmicro and macro-benthic animals. Various species presentin the gut included Navicula, Amphora, Cymbella, Synedra,Fragilaria, Oscillatoria, Zygnema, Spirogyra, Tribonema,Arcella, Keratella and Chironomus. In the case of T. khudree,the food items of all age groups include the filamentous algae,benthic diatoms, small crabs, fishes and insects (Dinesh,pers.obs.).

Reproductive biologyInformation is available on the breeding behaviour, season

and sex organs of mahseer since the nineteenth century itselffrom the anglers and naturalists. Beavan (1877) reported thebreeding period of mahseer as May to August withconspicuous local migratory behaviour. MacDonald (1948)noted that gonads of mahseer occur as a pair of elongated,light coloured, strap shaped bodies lying one on each side ofthe intestine, and lodged in the groove between the air bladderand the abdominal wall. The pioneering observation on thespawning of mahseer dates back to Cordington (1946). Thebrooder fish migrates upward from deeper waters to thetributaries for spawning but do not stay there after spawning(Badola and Singh, 1984; Nautiyal et al. 2007). David (1953)believed that the commencement of breeding is related to


29

the change in water temperature. Chaturvedi (1976) agreedwith this observation and concluded that the flood of clearwater accompanied by drop in temperature is the prerequisitefor spawning. Pathani (1983) recorded four groups of eggsin ripe females from Lake Bhimtal and Chaturvedi (1976)experimented on the monthly changes in the gonads of T. torfrom Lake Udaipur in Rajasthan. They reported that the fishbreeds there only once a year from July to September withpeak in August. However, Khan (1939) opined that mahseerspawns more than once a year. As far as the factorsresponsible for triggering spawning in hill-stream fishes areconcerned, it is a specific combination of temperature, pH,velocity, turbidity and rains, which collectively induce thefish to spawn (Dobriyal et al. 2000).

Thomas (1897) recorded that mahseer breed during thepost monsoon month and lay eggs in batches. Sehgal (1987)reported two breeding seasons, first during May- June andsecond during August-September, on the basis of thecollection of fertilized eggs and hatchlings from the riversof Himachal Pradesh. He observed that in the snow-meltrivers of the State, T. putitora spawns twice in an year, whenthe tributaries receive spate with rapid snow-melt waterinduce the local stocks to spawn. Studies by Mohan (2000)revealed that T. putitora spawns in batches and number ofbatches may depend on the environmental conditions. Heconcluded that the species has only one spawning seasonduring July-August. In this species, females outnumberedmales and average annual sex ratio was estimated as 1: 1.29.The total fecundity ranged from 3987 to 7320 in the spawnerswithin the size range of 190 to 250 mm total length. Nautiyaland Lal (1985a) reported that the fecundity was quite low(7076-18528) in lacustrine mahseer when compared withriverine fish (26,998-98,583) in similar climatic regime. Thefecundity per kg body weight obtained was 3375- 8944 (mean6,000) in the length range of 78.0 -137.7 cm and weight rangeof 3.5 to 23 kg.

The females of Himalayan mahseer commence to attainfirst sexual maturity at 40 cm of length in the river Gangaand 30.9 cm in the lakes of Kumaon. The smallest maturemale measured 36.5 cm (370 gm) and 20.7 cm in therespective environments. In the mountain stretch of the Gangain Garhwal, the males mature at 30-50 cm and the female at50-70 cm (Nautiyal, 1984). The calculated weight at the onsetof sexual maturity was 1119.21gm- the observed averageweight being 875.5 gm- and the age 3+ years (Nautiyal,1990). It was further observed by Nautiyal and Lal (1985b)that maturity in the species is directly linked to the growthrate of the gonads, which depends on the quality and quantityof food available. Significantly the testes of T. putitora werefound to possess higher growth rate implying early maturityin the males. The higher size of the ova was explained as anadaptive significance from the view point of food supply-reproduction relationship attributed mainly to scarcity oflarval food during monsoon, when the fish spawns. Studies

by Chaturvedi (1976) on the gonads of both the sexes of T.tor showed that the gonads undergo certain progressivechange as the fish attain sexual maturity. Chaturvedi (1976)also found that the number of ova per gram weight of ovaryvaried from 259 to 361 and the number of ova per gramweight of fish from 24.61 to 36.35. Desai (1973) afterextensive studies on T. tor reported that the ova diameterincreased progressively from April - September and thereafterdecreased gradually till March. The Gonado-Somatic Index(GSI) of females increased from March (2.85) to August(30.10) and declined in September (25.44) indicating thecommencement of breeding in July-August. The GSIgradually decreased from October (6.56) to February (4.17)giving indication of continuity of breeding until February -March. The GSI of male fish also showed peak values inJuly-August.

Based on the collection of partially spent wild broodersand one-week-old fry from the Harangi river (a tributary ofthe Cauvery), the spawning season of T. khudree has beenfound to be during September-October (Basavaraja et al.2006). On the basis of the residual eggs in the wild broodersand oocytes at different stages of development in the ovary,they also indicated that T. khudree is a batch spawner. Sincefingerlings are available in all seasons in the rivers of theWestern Ghats, it can be believed that mahseer breeds not,less than two times in an year in these rivers. In Kerala alsothe breeding of Mahseer takes place in the June-July andNovemeber-December seasons. The minimum size at firstmaturity is recorded as 180 mm (320g) and 280 mm (740g)for the male and female respectively in T. khudree. Thepresence of fry and fingerlings of the species in the smallchannels (with average width and depth of 3 and 0.5 m ,respectively) draining the Chalakudy River in Kerala clearlyindicates that the brood stock migrate to these very smallwaterbodies for spawing. The lodging period of the spawnerscan only range from a few hours to a few days as far as theextremely low carrying capacity and erratic waterflow ofthese channels are concerned (Dinesh, pers.obs.). Kulkarniand Ogale (1991) reported a higher weight of 900g forattaining sexual maturity in T. khudree. Basavaraja et al.(2006) reported that pond-raised T. khudree males attainedmaturity after one and a half years at an unbelievably lowerweight of 25-40g at Mangalore, where the temperature rangedbetween 25 and 310 C. Kulkarni (1971) has clearly followedthe structure of eggs and their further development in T.khudree and stated that the eggs are bright lemon yellow incolour merging on golden brown resembling the eggs ofGonoproktopterus kolus. The perivitelline space is small andthey absorb only a small quantity of water for increasing thesize from 2.5 mm (freshly laid) to 3.2 mm (after waterhardening).

Aquaculture prospectsMahseer was identified as a candidate species for


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aquaculture because of its sporting quality and excellentflavour of flesh since the last century itself (Day, 1876). Dhu(1923) judging the growth of mahseer fry in Mahanadi riverstated that it can be well cultured in the ponds. David (1953)indicated the possibility of culturing Tor mosal mahanadicusrecording a growth of 170 - 200 mm within four months.But no attempts were reported on the culture of the groupfor the next two and a half decades, the major constraintencountered might have been the non-availability of thestocking material. There was an apprehension that thesefishes could be reared only in cold waters which wascontradicted by Karamchandani (1972). He concluded thatthough T. khudree is an inhabitant of hill streams, it thriveswell in waters with high temperature ranges also. Badapandaand Mishra (1992) reported the transplantation of T. khudreeto Sonepur, Orissa during 1987 for a culture trial.

Kulkarni (1971) proved that mahseer is a good speciesfor aquaculture and attempted the commercial seedproduction of the group. National Bureau of Fish GeneticResources, Lucknow has identified T. khudree as a potentialcultivable species. The constraints identified were lack ofstandardized seed production technique, dearth ofinformation on the biology especially on the reproduction aswell as scarcity of spawners and seed. Breeding and larvalrearing know how are available for many species of mahseernow and it has been prioritized as a group not only foraquaculture but also for ranching. The copper mahseer isreported to be suitable for culture in ponds and is used forstocking in Tamil Nadu (Pisolkar, 2000). Since T. khudreegenerally shows a slow growth in the ponds and reservoirs,its culture trials were carried out in floating cages in openwaters (Kohli et al. 2002). After the culture period of 371days, total increment in weight (g) in the three cages was173.60, 217.74 and 358.55 with percentage survival of 46.67,56.67 and 35.35 respectively. Sunder et al. (1993) stockedgolden mahseer in flow through tanks (2m2) and after arearing period of 3-4 months, the fishes attained a size of50-65mm (0.095-0.250g) with a survival of 68.8-80.3%.While Tor putitora was used as a candidate species in cageculture, Kohli et al. (2005) could harvest the length andweight of 180-290 mm and 180-250 g respectively with asurvival percentage of 68.89 after 356 days. Raina et al.(1999) grew T. putitora in manured ponds, for an year, withartificial feed and obtained a survival rate of 55%. Islam andTanaka (2004) after conducting pond culture trials concludedthat Tor putitora is a highly promising species for commercialaquaculture and the fish performs well if proper dietaryconditions are met. Conducting culture trials in properlymanaged earthen ponds, National Research Centre forColdwater Fisheries could realize a size of 210 mm and 175g for T. putitora within one year. Ogale (2002b) reportedthat in village ponds near Lonavala, Maharashtra T. khudreehas grown between 600-900g in one year. Experimentsconducted in Lonavala (Ogale, 2002 b) proved that T. khudree

fingerlings could be grown to 110-120 g in monoculture at astocking density of 11,000/ha in 8 months with theconventional feed of rice bran and ground nut oil cake (1:1).Monoculture of T. putitora was also carried out at Lonavalaand the average growth obtained was 110 g and 90 g atstocking densities of 10,000 and 20,000/ha respectively.Badapanda and Mishra (1992) observed discouraging growthrate in T. khudree reared in ponds and concluded that thefish grows well only at lower temperatures. There are otherreports too, depicting that T. putitora and T. khudree arerelatively slow growers and cold-lovers (Pathak, 1991, Bazazand Keshavanath, 1993; Keshavanath et al. 2002; Sharma,2001). Therefore, lower growth rates are likely in confinedenvironments with relatively high temperatures.

From the above account, it is quite clear that there havebeen very few attempts for assessing the aquaculture potentialof the different mahseer species in India. Other than theNRCCF and College of Fisheries, Mangalore, no researchorganizations have come with encouraging results on mahseerculture. Freshwater aquaculture sector of the country has beenmainly revolving around the Indian major carps and theChinese carps since its inception aiming higher productionrates. So the endemic fishes especially the mahseers had notreceived due attention in the culture scenario. Introductionof the exotics must have resulted in the intrusion of thesespecies to the natural habitats of the endemics. At the sametime, increased protein production due to the introductionalso needs to be considered. So the need of the hour is totake up aquaculture programmes of different mahseer speciesin the pond and reservoir environments. Riverine fisheriesand stock enhancement programmes can also be linked withmahseer seed production and culture.

Nutritional studiesAquaculturists have been trying to find out nutritionally

balanced diet by incorporating different ingredients in variedproportions to realize better production levels. The resultsclearly indicated a positive correlation of sardine oil onweight gain of the fish. Incorporation of silkworm pupae asa protein source in the diet of Deccan mahseer was tried byShyama (1990) who found that it has no adverse influenceon flesh quality, the optimum level of inclusion being 60%.Spirulina was used as an effective protein source for thespecies by Keshavanath et al.(1986). Several experimentsand trials have been conducted at NRCCF to formulate dietsfor various life stages of golden mahseer by using localingredients like soyameal, silkworm pupae, rice/wheat starchetc. On the basis of these investigations, it was observed thatthe early rearing stages of mahseer up to advance fry/fingerlings (45 - 55 mm) require about 45% protein (Mohan,2002).

Islam (2002) after conducting studies in indoor andoutdoor systems on T. putitora under monoculture concludedthat the indoor culture of mahseer is discouraging and


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unprofitable and therfore, he suggested polyculture for betteryields. Production was 471.4, 541.9 and 497.3 kg/ha in theout door phase and 83.7, 170.5 and 161.5 kg/ha in the indoorphase respectively. Bazaz and Keshavanath (1993) reportedweight gains of 19.37-25.65 g in an experiment with fourdifferent types of feeds (37.12-39.8% protein) on T. khudreein 126 days. Butt and Khan (1988) reported that lower growthrate is associated with lower appetite and insufficient foodutilization due to carnivorous behaviour of the fish. Nautiyaland Lal (1985c) and Sharma (1987) observed that animalfood comprises a higher proportion of the natural food ofmahseer. Bazaz and Keshavanath (1993) conforming to theobservation made by Srinivasamurthy and Keshavanath(1986) reported that protein requirement of T. khudree is 40%.Sunder et al. (1998) reported better growth, survival and feedconversion with 45.4% crude protein in T. putitora afterconducting a growth trial with six formulated diets containing21.4-50.2% crude protein. In an early study, Joshi et al. (1989)reported 35% crude protein as the best for growth and feedefficiency in T. putitora.

Srikanth (1986) reported that the ideal diet for T. khudreemay contain 40.39% crude protein, 6.56% crude fat, 25.99%carbohydrate, 7.06% crude fiber, 10.67% ash and 9.33%moisture with a calorie content of 3.65 kcal/g. The averagedaily increment was 0.51g and net gain in weight was 54.68gwhile the experimental diet was used. Keshavanath et al.(1986) reported that incorporation of 17 á methyltestosterone@ 2.5 ppm to the diet has improved the growth and survivalin T. khudree. Hormone feeding enhanced muscle proteinand fat contents in the fish meat and the organolepticcharacteristics remained unaltered (Keshavanath, 2000).

Artificial propagationArtificial fecundation of eggs of Tor khudree was

successfully carried out on a large scale for the first time in1970 (Kulkarni, 1971). Natural breeding of mahseer has beenreported in reservoirs, lakes and ponds during the monsoonand in other seasons (Kulkarni and Ogale, 1978; 1991; 1995).They attempted breeding of four species of mahseer usinghypophysation and stocked them in ponds. Successfulspawning of pond raised mahseer, T. khudree using inducingagents like pituitary extract and Ovaprim was reported byNandeesha et al. (1993). The mature fishes could be spawnedwith injection of either pituitary extract or Ovaprim, followedby stripping. In similar trials conducted at Mangalore, acoastal place, away from the original habitat of the mahseer,Keshavanath et al.(2006) observed that cryopreservedspermatozoa of the species performed comparable (P>0.05)to the normal spermatozoa in terms of fertilization rate andquality of hatchlings. Fertilized eggs incubated in Mangaloreat 27–28oC took 60 hours for hatching and 95 hours for yolksac absorption, while it took 120 hours and 238 hoursrespectively when maintained at 20–24oC in Harangi.

Tripathi (1978) attempted breeding of T. putitora by

stripping the eggs on a small scale. Kulkarni and Ogale (1978)elaborated this method fertilizing more than five lakh eggsof T. khudree every year since 1974. Jan and Dogra (2001)developed the brood stock of Tor putitora in ponds collectingthe fingerlings of the species from Anji Stream (Reasi) inUdhampur of Jammu & Kashmir. After a period of 3 years,the farm reared breeders were given a single dose of Ovaprimand fertilized eggs were obtained by stripping. Even though,the production rate attained was low, the effort taken by theteam seems significant since it proved the possibility ofestablishing small scale hatcheries with limited facilities.Another important achievement in the artificial breeding ofmahseer was the effective transportation of fertilized eggsby air in moist cotton wool, without water, over long distances(Kulkarni, 1984).

Ogale and Kulkarni (1987) reported that T. khudree andT. tor could easily be hybridized using the eggs of the formerand milt of the latter. Fertilization was almost cent percentand hatching rate was 90%. The resultant progeny showedintermediate characteristics of both and the growth rate wascomparable to the parents. They have further bred thesehybrids (females) with the T. khudree males and providedsatisfactory results. Induced breeding of golden mahseer wassuccessfully done at Dhakrani, U.P. State Fish Farm with80–85% fertilization and over 60% hatching rate (Panday etal. 1998). It took a period of 72 to 120 hours for the hatchingprocess. Mohan (2002) and Mohan et al. (1998) observedthat finely emulsified chicken egg yolk followed by smashedgoat’s liver particles have given excellent results in the larvaland post larval rearing of Himalayan mahseer.

Short term preservation of spermatozoa of Deccanmahseer was carried out by Basavaraja and Hegde (2005)reporting that the spermatozoa density varies with the seasonand it could be preserved in a motile state for 4–5 days whichsuggests the application of this technology for implementingmore effective propagation programmes. Patil and Lakra(2005) reported the successful sperm cryopreservationprotocol for two mahseer species, T. khudree and T. putitora.

The Tata Power Company Ltd., Lonavala, Maharashtradid pioneering work on the conservation, breeding andartificial propagation of mahseers. Under the leadership ofLate Dr. C.V. Kulkarni and Mr. S.N. Ogale, the TPCLstandardized the commercial seed production of five speciesof mahseer, viz. T. khudree, T. mussullah, T. tor, and T.putitora and augmented the mahseer stocks in the reservoirsand rivers in many States by supplying fry and fingerlings.DCFR established a flow through hatchery, and every yearthousands of advanced golden mahseer fry are beingproduced and distributed for ranching the mahseer–depletedwater bodies. The design is simple, small and temporarywhich can be dismantled at a very short notice in emergencyconditions. In Karnataka, mahseer seed production is carriedout in Harangi Hatchery of the Department of Fisheries since1997 with the support of the TPCL and the College of


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Fisheries, Mangalore. The Department of Fisheries, Govt.of Kerala through its agency for the Fisheries ResourceManagement Society (FIRMA) established a mahseerhatchery in Wayanad District and attempted the artificial seedproduction of T. khudree with the technical assistance fromNRCCF. Results are yet to be published.

Game fisheries, conservation and managementImportance of mahseer as a game fish has tremendous

potential in India owing to the rich resources in terms ofspecies diversity and water availbility. Kulkarni (1981)warned that mahseer, the king of Indian rivers, is in dangerand highlighted the need to be protected. Raizada also (1981)gave a depressing account recommended to have more“mahseer projects” for conservation purpose. Menon et al.(2000) listed the reasons like use of gill nets of smaller meshsize, year round fishing activity, fishing with explosives,ichthyotoxic plants, etc., for the disappearance of mahseerpopulations. Ogale (2002a) expanded the list to include (1)degradation of ecological conditions of aquatic systems, (2)indiscriminate fishing of broodfish and juveniles, (3) rivervalley projects, (4) industrial and anthropogenic intervention,(5) use of explosives, poisons and electrocution and (6)introduction of exotic species. Nautiyal (1989) pointed outtwo natural constraint like delayed maturity, low fecundity,long hatching period of 60–80 hrs at 24–28o C and slowgrowth rate and man made constraints like habitatfragmentation, and overexploitationas the factors responsiblefor the decline of Himalayan mahseer in the rivers. Oliver etal. (2007) reported about a special type of bag net used bythe fishermen which is operated across the water falls in thedown stream of the reservoir in Harangi River in Karnatakaduring the breeding migration of mahseer. It is also reportedthat fingerling and fry fishing of mahseer by fishermen fortheir subsistence is a major issue in Umiam reservoir ofMeghalaya which has resulted in the drastic decline of theirpopulation (Vinod et al.2007). Jayaram (2005) discussedmany reasons for the decline of the mahseer specifically inthe Western Ghats. It is pointed out that extensivedeforestation that have taken place in the Ghats during thelast hundred years might have been one of the major reasons.In the North East Himalayan region, mahseer catch is reportedto be declined to the level of 45–60%. The tribes and theillegal migrants have started netting the fish of even 100 gsize (Raina et al. 1999). Kumar (1988) has reported thedisappointing situation of decline in catch and size of mahseerin Central Himalayan region. Even though the Tor speciesonce contributed a significant proportion of the natural stockof fish in India, their populations have dwindled to such anextent that they have been categorized as criticallyendangered species (CAMP, 1998). Jayaram (2005) noticedmahseer specimens with fungus-infested fins mainly due toindiscriminate disposal of plastic bags containing remnantsand left over of eateries in certain sanctuaries. There are

reports depicting that fish ladders provided in head watersof certain irrigation projects are ineffective and act as trapsrather than fish passes (Raina et al. 1999). Thorough studiesare required on the migration behavior of mahseer on anational basis, which could serve as a base for the design ofappropriate fishways across the dams (Nautiyal, pers. com).

Based on the information collected from several streams/rivers covering twelve river basins representing the Statesof Karnataka, Kerala and Tamil Nadu part of the WesternGhats, ten mahseer sanctuaries are proposed in various riversin Karnataka (Basavaraja and Keshavanath, 2000). They havealso suggested in situ and ex situ conservation measures forthe group. Traditional conservation measures like declarationof areas as sanctuaries, closed seasons for fishing, mesh sizeregulation for gears, reserving certain stretches for rod andline only, enforcement of bag-limits and catch limits andpenalty for adopting destructive fishing methods etc. willhelp to a great extent in the mission. Department of Fisheries,Karnataka, launched a programme in 1987 on “Rehabilitationand Development of Mahseer Fishery in the Rivers andReservoirs of Western Ghats”. Fishery management of T.khudree is done effectively in Cauvery River as WildlifeAssociation of South India is taking care of stocking theleased stretch of the river with mahseer fingerlings(Shanmukha, 1996). Currently, the fishing is open to licensedsport fishermen from October to May. Angling is the onlypermitted fishing method.

Government of Himachal Pradesh has incorporated aspecial clause in the Fisheries Act that fishing during thebreeding season is made a cognizable non-bailable offencewith imprisonment upto three years. Sarma and Bhuyan(2007) suggested that the conservation of mahseers inMeghalaya can effectively be undertaken through theintervention of local ‘Dorbar’, a unique self village governingsystem prevailing in the State. In fact, the most critical aspectis to create awareness among the common man about theneed to protect the endangered fishes. Mohan et al. (1998)are of the opinion that there are two effective ways toconserve fish germplasm; the first method is to allow theleft over stocks to multiply and second to stock the depletedwater bodies. Whereever impoundments have been built orare coming up, establishment of mahseer seed productionunits should definitely be a primary requisite. Programmesorganized by NBFGR in the Kumaon region wherein“Mahseer Bachao Gosthis” were launched to conserve theendangered mahseer have contributed positively in theconservation and they are worthy of replication in otherplaces. Socio-economic aspects of conservation and the roleof anglers have been evaluated in selected areas exploringthe possibility of community participation. Menon et al.(2000) suggested that suitable segments of the rivers withmahseer should be identified for establishment of ‘fishsanctuaries’. It is noticed that, fishing is prohibited onreligious grounds in certain stretches of Ganga (eg. at Har-


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ki-pairi, Haridwar and Muni-ki-Reti, Rishikesh) and also insome temple ponds along Gomti in the Kumaun region ofUttarkhand which helps to provide safer areas for the fishpopulation. Jayaram (2005) mentioned about some protectedareas by the side of temples as in Dehu, Alandi on riverIndrayani, Sringeri on Tungabhadra, Ramnathapura onCauvery and certain water bodies of the sacred groves wheremahseer is guarded. Other places of mahseer conservationinclude Thingale in Sita River of Udupi District, Shishila inSouth Canara District and Hariharapura in Thunga River. Inanother place called Sringeri, the depth of the river rangesbetween 15 and 50 cm and with the clear water fishes arehighly visible. As the biomass of the area is too high, minorchanges in the water quality may affect the whole population.Oliver et al. (2007) reported about a massacre of mahseersat Shishila temple in Karnataka wherein about 10 truck loadsof mahseers were killed by poisoning with endosulphan as aresult of rivalry between two communities. Such kind ofincidents can be avoided only by creating awareness amongthe local people about the importance of species conservationand ill effects of using indiscriminate fishing methods. Alsothe legislation has to be strengthened against the culprits whodirectly or indirectly indulge in such activities. InRamnathapura of Cauvery, mahseers are conserved inprotected areas separated by rubbles. The mid stretches ofCauvery characterized by sinuosity of riffles and deep poolsalso offer an ideal habitat for mahseer (Ganesh and NagendraBabu, 2005). The deep pools around Galibore, Bheemeshwariand Doddamakkali having depth of 5–15 m, width of 250–300 m and length up to 300–400 m even in summer offerexcellent refuge even for the larger fishes of 30–40 kg.Certain areas are declared as sanctuary and poaching is almostnil due to strict vigilance. Interestingly, a few poachers inthe stretch have been given an alternate avocation to performthe patrolling duty of watchmen to enable them to earnlivelihood and prevent them from engaging in poachingactivity. Another way of conservation of mahseers is alsonoticed in the west flowing rivers of Karnataka, viz. Bedthi,Aganashini, Sita and Nethravathi where these fishes areconsidered as Devarameenu (God’s fish) and the peoplethemselves take cudgels if the fish is caught.

Many places in India are becoming the importantdestinations for the global tourists as the new concept of eco-tourism has been strenghthened in many States. This can wellbe blended with mahseer fishing in the hill areas to attractthe local as well as foreign anglers. Tourism generates muchneeded revenue, creates local awareness of the importanceof species conservation and also provides incentives to thelocal people. In Madikeri of Karnataka such a practice hasbeen initiated by Coorg Wildlife Society in a stretch of 28km of the river. Recognizing the results obtained by theSociety in terms of Mahseer conservation in the river, theDepartment of Fisheries has awarded the Society with anadditional 92 km of the river stretch in Coorg since 2006 for

the next 5 years. These include about 55 km of the riverCauvery, 21 km of the river Barapole and about 16 km ofMadapur River.

It is also worth mentioning about the opinion that theconservation programmes of mahseer by artificial stockinghas led to the production of hybrids and the quality of theseoff springs are not known. Recently, Das (2007) alsocautioned about the alteration/extinction of gene pools ofthe species/stocks by cross breeding or hybridization andback crossing. This issue need to be addressed with dueimportance as far as the gene pool conservation is concerned.Of late, the Society is reported to have started the adoptionof habitat restoration strategy, though it is expensive and timeconsuming. With this program, the Society has initiated theidentification of Essential Fish Habitat (EFH) factors relatedto waters and substrates necessary for spawning, feeding andgrowth for attaining maturity of these endangered species. Itis suggested that all the activities which have the potential toaffect the EFH have to be discouraged. This can be taken asa model for conserving endangered fishes wherever possible.The Bhimeswari Camp is another location in the RiverCauvery in Karnataka which attracts the anglers even fromabroad. The anglers after obtaining licenses from WildlifeAssociation of South India (WASI) are permitted to fish withhook and line. The fishes caught are unhooked and releasedback to the river after taking weight and making otherdocumentations. Likewise, in Jammu & Kashmir, HimachalPradesh and Uttaranchal also fishing regulations allowangling of mahseer through permits issued on daily, weeklyor yearly basis for the anglers and fishers (Chauhan et al.2007). Hitherto no reports are available on the fate of thefishes after getting unhooked and released back to the river.But it can be assumed that many of them may die owing tothe exhaustion, injuries and associated infections. Thesefishes will be more vulnerable to fishing gears because ofthe impaired swimmimg efficiency. Shyla et al. (2007)suggested that Murivenna-a herbal oil used in Ayurveda canbe effectively used to heal the wounds and check the mortalityof injured fishes after conducting preliminary trials inunhooked mahseers and catfishes. The use of this ayurvedicdrug may be promoted after conducting comprehensivestudies at the field level.

Livelihood and nutritional securityIt is appropriate to discuss the role of mahseers in ensuring

nutritional security of the forest inhabited primitive tribes ofthe Western Ghats. Kadar, Malayar and Muthuvar of theGhats are dependent on the forest resources for theirlivelihood and the hill stream fishes serve as their majorprotein source (Dinesh and Abraham, 2007; Dinesh et al.2007). In Nilambur forests of Kerala, Cholanaikkan(Manchery Tribal Colony) which is one of the most primitivetribal communities of Asia that depend heavily on mahseerfor their daily bread. T. mussullah that has a patchy


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distribution in the River Chaliyar is the major species caught.As the fish has thick scales and tough meat, the qualitydegradation is slower and that makes it a preferable speciesfor the tribes both for consumption and sale. Althoughorganized marketing system, fish preservation techniques andvalue addition are yet to be introduced in these places, tribesusually earn approximately Rs.100/- for a day’s catch.Interventions on the marketing of the produces by theDepartment of Forests and Wildlife or other responsibleagencies will help to reduce the exploitation by themiddlemen during marketing. Another issue related withmahseer fishing and consumption is that local tribes believethat mahseer meat can not be consumed in certain seasonsowing to the presence of some toxic material in it which isreported to cause severe vomiting problems when consumed.Further studies are required to investigate the issue in detail.Tribal empowerment issues of the Western Ghats could bebetter addressed by incorporating fish-related activities as acomponent which may indirectly help the mahseerconservation programmes. Angling facilities extended inthese areas in association with eco-tourism would be a goodsuggestion, where tribes could be accommodated for relatedavocations to earn their livelihood. Kumar (2000) reportedthat mahseers have been of considerable importance to thelocal fishermen in North India because of their large size,hardy texture, high commercial value and longer shelf life.Kalita et al. (2007) observed that organized mahseer farmingcan become a vehicle for rural economic growth, apart fromproviding sustainable supplies of this fish caught during sportfishing and through commercial farming.

CONCLUSION

For the first time, an international conference on mahseerstotally dedicated to this group of fishes was organised in2006 by the Malaysian Fisheries Society with the activecolloboration of INFOFISH, Food and AgricultureOrganization (FAO) and Network of Aquaculture Centres inthe Asia-Pacific (NACA) along with several other agencies.The conference highlighted the importance of this group offishes and brought out a declaration based on the deliberationsmade in the conference.

• The mahseer is a cultural icon of diverse economic,recreational and conservational value in rivers of elevenAsian nations, with many species transcending country/national boundaries.

• The mahseer is an integral component of the aquaticecosystem and an important indicator of its health andsupports the livelihood of many rural, indigenous,ethnic groups in Asia.

• The strategies that need to be developed to maintainthe sustainability of mahseer populations are dependenton the effective utilization of available information onthis important and iconic group of fishes.

• There is an urgent need to collate the availableinformation and policy developments.

• The delegates also identified the necessity to usemolecular techniques to sort out the taxonomicambiguities as it is important from the view points ofbiodiversity and conservation.

The above points are of great relevance in the Indianscenario also and much bigger efforts are needed to conservemahsers and exploit their potential as sport and food fishes.First, the rapid developments in the molecular taxonomyshould be taken to advantage to solve the speciesidentification and distribution issues in mahseers. Its valueas a sport fish has been better recognised and the opportunitiesavailable to take advantage of the natural availability of thisspecies in various locations to develop mahseer based eco-tourism should be exploited. The potential of mahseer as anaquaculture species in combination with other species hasalready been recognised, though growth rate in stagnantponds seems to be low. Development of suitable feeds wouldhelp in improving the growth rate. Though nutritional studiesconducted on this species have provided the basic informationon the requirement for the macronutrients, studies on therequirement of micronutrients are almost unknown.

The technology of breeding of mahseer has beenstandardized by the TPCL and the DCFR. The breeding andconservation technologies for Deccan mahseers inMaharastra has opened up new opportunities for theconservation of fish through the involvement of privatesector. Dissemination of this idea to various States of Indiaand involvement of the private sector agencies would helpin scaling up the results obtained in Maharashtra. Thoughmany States have commissioned the mahseer hatcheries atthe Government level, seed production in adequate numbersis not being carried out due to many constraints. The projectinitiated by the Coorg Wildlife Society on Essential FishHabitat (EFH) restoration programme in Karnataka appearsto have vast potential and this approach that helps to conservefish in their natural environment could be replicated in otherpotential areas. As the tourism is likely to increase, creationof such EFH areas may help to attract tourists to those areas.As the fish respond to artificial feeding, the opportunitiesfor developing such ecosystem based fish aggregation centresare very high. The recent effort of the Central Institute ofFisheries Education in bringing out a ‘state -of- theknowledge book’ on Mahseers that can be used by variousstakeholders is a step in the right direction to conserve thisspecies through education. Conservation programmes havebeen taken up in diverse geographical locations (Nautiyal,2006) and worthwhile efforts need to be replicated to havegreat impact.

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Taxonomic status of marine pelagic fishes of India, research priorities andconservation strategies for the sustainability of their fisheries

P S B R JAMES

Former Director, Central Marine Fisheries Research Institute, Cochin, Kerala 682 018 India

ABSTRACT

The paper briefly reviews the taxonomic status of the marine pelagic fishes of India, lists the research priorities andconservation strategies concerning these fishes. While the taxonomic status of commercially important species/groupsof pelagic marine fishes is fairly well determined, the need for such studies on all other lesser known species is pointedout. In the present context of high fishing intensity, minimizing the effects of fishing based on certain biological attributes,would ensure the sustainability of marine pelagic fisheries and the conservation of species.

Key words: Conservation, Fishes, India, Marine, Pelagic, Taxonomy

Marine fish production in the country increased from 0.52mt in 1950 to 2.71 mt in 2006. Pelagic fin-fishes contributed55% of the total all India marine fish production. West coastof India contributes to the bulk of pelagic fish catches. Thereare about 250 species of pelagic fishes belonging to 12families but only 60 species belonging to seven groups,including the oil sardine, lesser sardines, anchovies, Bombay-duck, ribbonfishes, carangids and the Indian mackerel formthe major fisheries (Pillai & Katiha, 2004).

Certain unique biological characteristics andenvironmental parameters together cause wide oscillationsin the catches from year to year. The single species fisheriesof the oil sardine, Indian mackerel and the Bombay-duckeasily tilt marine fish production of the country in any year.Therefore, sustained production of marine pelagic fishes iscrucial for maintaining and enhancing total marine fishproduction of the country.

Hitherto, the country’s efforts to increase marine fishproduction have been focused only on commerciallyimportant species. Therefore, taxonomic, biological andfishery oriented studies have been mostly limited to, butintensified on such species. Sixty years of continued andmostly uncontrolled exploitation of marine fisheriesresources in the coastal region, facilitated by the open accesssystem coupled with modernization of crafts and gears, ledto overcapitalization and over-fishing of some resources.Though some offshore and oceanic resources remain to be

tapped fully, the situation, as far as the coastal resources areconcerned, warrants taking remedial measures, for the seedsof destruction of resources and degradation of theenvironment are evident for quite some time.

In this context, the present paper reviews the taxonomicstatus of marine pelagic fishes, research priorities andconservation strategies for the sustainability of their fisheries.

BIOLOGICAL AND FISHERIES CHARACTERISTICSOF MARINE PELAGIC FISHES

Biological Characteristics: Through belonging to distinctfamilies, the marine pelagic fishes have certain uniquebiological characteristics. Many of the species form massiveschools and migrate long distances along the coasts and frominshore-offshore and vice-versa. They grow very fast but haveshort life span. Breeding process is quite prolonged, oftenthroughout the year, shedding the gametes in batches at shortintervals. They are highly fecund; eggs and larvae are small,transparent and pelagic. They feed on plankton.

Fisheries Characteristics: The pelagic fisheries arecharacterized by the dominance of the oil sardine (Sardinellalongiceps), the Indian mackerel (Rastrelliger kanagurta) andthe Bombay-duck (Harpadon nehereus). These speciestogether account for more than a quarter of total marine fishlandings in any year and hence adverse effects of any fisherydependent or independent (environmental) factor on any ofthe species would tilt the total marine fish production to thenegative side and conversely, a favourable factor, to thepositive side. Such a vulnerable situation often causes socio-economic upsets along the west coast, where these fishesare prevalent and predominant. While these are highlyfluctuating fisheries, there are others, despite continuous and

*Present address: No. 832/27, 3rd B Main, 2nd Cross, Prem NivasRoad, Kammanahalli

P.O., St. Thomas Town, Bangalore, Karnataka State 560 084India.

E-mail:[email protected]

40 JAMES [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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intense fishing over the years, exhibit increased production.They are exemplified by the lesser sardines, Hilsa spp.,Whitebaits, Thryssa spp., Coilia dussumieri, carangids andribbonfishes. The only fishery which had declinedsignificantly was that of the unicorn cod (Bregmacerosmclellandi). Another characteristic is the area-specific natureof the dominant species. The oil sardine, Bombay-duck andunicorn cod are mostly restricted to the west coast, thegrenadier anchovy (Coilia dussumieri) to the northwest andnortheast coasts. Research indicated that the distribution andabundance of certain species is restricted to certaingeographic regions mostly dependent on environmentalconditions and food availability, which also fluctuate andvary from year to year. Table 1 shows the average landingsof pelagic fin-fishes and their percentage contribution duringthe period 1990-2005.

TAXONOMIC STATUS

Taxonomic research on fishes in general and other taxaof the animal kingdom was conducted extensively in theearlier periods by the Zoological Survey of India and theIndian Museum at Calcutta. Limited taxonomic research wasalso carried out on fishes by several universities and Institute.The Central Marine Fisheries Research Institute (CMFRI),which is primarily concerned with research and developmentof marine organisms, from the production point of view, madeseveral taxonomic contributions on marine invertebrates,fishes, reptiles and mammals, mostly in the 60s and 70s.Quite a few of these works are of classical nature and theonly ones of their kind to-date. By and large, all the majorand minor marine pelagic species have been studied and theresults have been published. These studies have been mostlybased on classical and traditional methods of taxonomyincluding morphometric measurements, meristic counts,

body shape, colour etc. However, difficulties have beenexperienced in identification of species due to overlap inmorphometric measurements and meristic counts. Colourpatterns, though quite diagnostic in several species, soondisappear on death and altogether vanish on preservation. Inmany species, especially the coral reef fishes, colour patternsremain important tools for identification. In traditionaltaxonomic methods, to further supplement and confirm theidentity, certain anatomical features, like dentition, gill rakers,pyloric caecae and osteological characters have been takeninto consideration. The electrophoretic studies have also beenmade use of for confirmative evidence.

Table 2 indicates the major taxonomic categories of marinepelagic fishes and their species diversity. In the past, in-depthtaxonomic research was conducted mostly by the CMFRIon the sardines, whitebaits, wolf herrings, other clupeids,coastal and oceanic tunas, seerfishes, mackerel, ribbonfishes,carangids, Bombay-duck, halfbeaks and mullets.

Very extensive and exhaustive research on the taxonomyof these pelagic fishes have been accomplished based on field

Table 1. The average landings of pelagic fin-fishes and theirpercentage contribution during 1990-2005

Group Catch (tonnes) (%)

Oil sardine 224,655 18.2Mackerel 163,832 13.1Carangids 142,385 11.4Ribbonfishes 129,540 10.4Anchovies 116,098 9.3Bombay-duck 110,696 8.6Lesser sardines 97,306 7.8Other clupeids 47,720 3.8Tunas and bill fishes 45,950 3.7Seer fishes 43,950 3.5Hilsa shad 25,359 2.0Wolf herrings 15,251 1.2Barracudas 14,040 1.1Other pelagics 70,372 5.6Total pelagics 1,246,901

Source: Pillai & Katiha, 2004

Table 2. Major taxonomic categories of pelagics and theirspecies diversity

Family Group/Species Species number

Clupeidae Oil sardine* 1Lesser sardines*(including rainbow sardines) 14Hilsa spp. and other shads 15Whitebaits* 24Thryssa and Thrissocles spp. 10Wolf herrings 2Other clupeids 40

Scombridae Coastal tunas 5Oceanic tunas 2Seerfishes and wahoo 5Mackerels* 3

Trichiuridae Ribbonfishes* 8Carangidae* Round scads 2

Golden scads 6Hard tail scad (horse mackerel) 1Jacks 17Black pomfret 1Others 19

Harpodontidae Bombay-duck* 1Stromateidae Pomfrets 2Coryphaenidae Dolphinfishes 2Rachycentridae Cobia 1Mugilidae Mullets 22Sphyraenidae Barracudas 7Exocoetidae Flying fishes 10Bregmacerotidae Unicorn cod 1

Others 19Total Pelagics 240

*Major pelagicsSource: Pillai & Katiha, 2004

April 2010] TAXONOMIC STATUS AND CONSERVATION OF MARINE PELAGIC FISHES OF INDIA 41

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collections, representative of their geographical distribution,in the seas around India. They have covered examination ofholotypes, paratypes and syntypes of species. Synonymiesof individual species, status of nominal species,nomenclatorial changes, earlier revisions and reviews,scanning of world literature on the concerned species havebeen taken into consideration for confirmation of speciesidentity. Such studies indicated the possibility of wrongidentifications due to close external resemblance, concurrentoccurrence of similar looking species in the same area andinadequate sampling. Due to various reasons, some welldefined species could exhibit wide variations in shape, colour,distribution and even reproductive behaviour, when they areconsidered from different populations, stocks or races of thesame species. Some attempts have been made to deciphersuch populations of oil sardine, mackerel, Bombay-duck andthe skipjack tuna. Results indicated the clusters overlappingand confluence of populations and the need for properdelineation of population genetic parameters. This has greatimplications for fishing since, if the population ishomogeneous, fishing at any one place can affect the stockat every other place. If the population is heterogeneous,fishing at one place would not affect the stocks at other places.

To date, the FAO field identification sheets for the fishesof the western Indian Ocean remains the most recent efforton the taxonomic status of Indian marine pelagic fishes andothers as well. There is need to conduct such exercisesperiodically, exclusively for the Arabian Sea, Bay of Bengaland the southern Indian Ocean. Systematic studies are neededon several other marine pelagic fishes like the barracudas,flying fishes, belonids, billfishes and others, especially withreference to biodiversity documentation and ecosystem-basedfishing. However, biodiversity should not be synonymisedwith taxonomy since the latter is the foundation for allbiodiversity programmes. It may suffice for biodiversitypurpose to identify a species but taxonomic study goes deeperto examine all nominal species of a genus to fix their statusbased on several considerations (Lundgren et al. 2006). Therecould be several new species or wrong identifications forwell known species. Often, a number of larval or juvenilecharacters may be retained or they would disappear as thefish grows. All such phenomena need critical study for properidentification. Lumping of species and splitting of speciesalso occurs sometimes.

Taxonomic research in general in the country appearsneglected. It is clearly a retrograde step. Serious efforts areneeded to bring back the subject to its rightful place toprogress systematically with all other areas of study for whichtaxonomy is the key. Universities and several institutions inthe country should establish departments/divisions fortaxonomy and promote study and research by providingnecessary incentives and employment opportunities. Inaddition to traditional methods of taxonomy, more modernapproaches like molecular taxonomy and genome mapping

have to be encouraged for faster identification and extensivecoverage of geographical areas for animal identification.

RESEARCH PRIORITIES

Obtaining continuing yields from a living resource is atraditional goal in fisheries management. Populations orstocks fall below levels that provide adequate yields or whichfail to meet other specified reference points due to severalreasons. Key biological characteristics of fishes,environmental factors, habitat alterations, pollution andfishing seriously impact fish production. Fish stockfluctuations and declines have to be continuously monitoredand managed for they cause economic and social hardships.Marine pelagic fishes and their life-histories andenvironmental conditions under which they live andpropagate need further research to manage their fisheries.Voluminous data and information have already beengenerated by the CMFRI in the past, but focused attentionon some critical areas mentioned hereafter may be requiredin future.

Age and Growth: Pelagic fishes have short life span, growvery fast and breed continuously almost throughout the year,shedding the ova in batches. This makes it difficult toaccurately determine their age and growth because of overlapin recruitment and successive resultant broods. At present,age and growth of almost all pelagic fishes are determinedby indirect methods. Attempts and research are needed fordevelopment of direct methods of tagging, and determiningdaily or monthly growth rates by examination of hard partslike otoliths under electron microscope (Quasim, 1973;Uchiyama & Struhsaker, 1981; Waldron & Ferneke, 1997;Campana & Thorrold. 2001; Santiago & Arizzabalaga, 2005).Depending on the accuracy of methods used, determinationof actual age of the fish may vary. This will have seriousimplications for determining populations, if any, in pelagicfishes like the oil sardine, mackerel and others.

Fecundity: Earlier determinations of fecundity of severalspecies of pelagic fishes could be suspect because ofprolonged, intermittent and batch spawning in most of thespecies. Proper identification of maturity stages in theprogressive scale as well as the digressive scale is essentialin such cases for determining the correct fecundity. Thenumber of ova in each batch spawned and the number ofbatches have to be calculated for arriving at the totalfecundity. Fecundity calculations have implications forestimating stock sizes via the sex-ratios.

Egg and larval surveys at sea: This area remains poorlyinvestigated. Location, identification and quantification ofeggs and larvae and calculations of natural mortality ratescan directly help to predict the short-term fisheries of manycommercially important fishes of the country. Indirectly, suchstudies will enable assessment of total stocks to confirmstatistical estimations.

Recruitment: A very crucial aspect is to understand the


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strength of age-classes and hence the total stocks. The successand failure of recruitment beyond the critical life stagesdetermine the magnitude of the fishery. Abundance of recruitsmay retard growth and cause reduction in fecundity. Therecan be low recruitment despite continued presence ofspawners. Current stock-recruitment models assumerecruitment is zero when stocks are extinct. Therefore, thereis need to develop new stock-recruitment models.

High fluctuations in fisheries: Certain fisheries like thoseof the oil sardine, mackerel and the Bombay-duck highlyfluctuate from year to year. Several environmental factorsare found to be responsible for the same. Amongst them, theonset and intensity of the monsoon, sunspot activity, seasurface temperature, current pattern change, variations insalinity, dissolved oxygen, sinking of offshore waters, sealevel and availability of nutrients in coastal waters arebelieved to be important (Murty, 1965; Murty and Edelman,1970; Rao et al. 1973; Longhurst. and Wooster, 1990; Murtyet al. 1990; Pillai, 1991; Madhupratap et al. 1994;Jayaprakash, 2002; Vivekanandan et al. 2008). As the stockstrengths are dependent on success of spawning, recruitmentand natural mortality, work at sea to monitor these phenomenaassume importance in addition to study of other parameters.A combination of rate of exploitation and changes inenvironmental factors may also cause collapse of stocks. Theimpending climatic changes due to global warming mayfurther affect stocks of highly migratory species. They needcontinuous monitoring.

Schooling behaviour: Not much research has been doneon the migration and schooling behaviour of marine pelagicfishes. This is of immense value since schooling fishescontribute to high commercial abundance. Such fishes haveto be tagged and their movements tracked using all modernmethods including use of acoustic and telemetric tags. Theschools should also be scouted using remote sensing methods.The schools are generally considered to be spawning, post-spawning or feeding congregations. The composition of theschools, timings, seasons and reasons and routes have to befully elucidated. Schooling fishes are highly vulnerable tocapture at the time of their migration. Even if populationsize of such species decreases, they can still be targetedprofitably and with continuing efficiency. Fortunately, suchspecies, the schools of which are continuously exploited, e.g.,ribbonfishes, sardines, anchovies, mackerel, scads, and tuna,have not declined in their strength. However, with increasein intensity of fishing due to high demand for fish, there couldbe signs of decline in catches, which have to be continuouslymonitored. Work of the type done by the erstwhile PelagicFisheries Project along the west coast of India on schools offishes at sea needs to be revived and continued.

Trophic models: Very little research has been conductedat sea on the food chains and food webs to understand theircomponents, factors controlling their fluctuations and thelinks between them and the fish populations. The plankton

feeders like the sardines, mackerel and other fishes dependon availability of suitable planktonic organisms. Any upsetsin the food chain from the availability of nutrients in coastalwaters to upwelling and movement of water masses andcurrents can cause wide fluctuations in the catches of thesefishes. The abundance of various other species up the chainwould in turn govern the abundance of higher categories offish. Therefore, knowledge of seasonal variations in trophicchains is important to understand the availability of fish. Suchresearch should lead to development of trophic models basedon time series data.

Predictive models: Some attempts have hitherto beenmade to forecast the fisheries of some species of pelagicfishes based on environmental factors and were foundsuccessful (e.g., the oil sardine). Attempts have also beenmade to understand fluctuations through mathematicalmodeling of fishery dependent and independent factors. Thehighly variable recruitment patterns, dependence on phyto-and zooplankton and the environmental factors that controlproductivity, climate and other oceanographic phenomenadetermining pelagic fish abundance have to be consideredtogether for developing forecasting models. Recent researchat CMFRI on forecasting of fisheries using Markov chainmodel appears advancement in this direction (Ayyappan &Pillai, 2005).

Genetic divergence in species: Research on molecularcharacterization of important marine pelagic species usingDNA sequences should be intensified for speciesidentification as well as to distinguish populations, if any, inwell established species.

Fish aggregating devices (FADs) and Artificial reefs(ARs): Recent studies conducted in the country by CMFRIand a few other agencies in different locations indicated theyare beneficial to fishermen because of capturing valuablespecies like the tuna, carangids and others. The structuresbasically provide shelter and forage. However, the economicsof operation, durability, and their impacts on other kinds offishing activities in the vicinity need detailed studies (MohanJoseph & Jayaprakash, 2003).

STRATEGIES FOR CONSERVATION

According to the FAO estimates, half of the major fishstocks in the world are fully-exploited (close to the maximumsustainable yield-MSY), another quarter overexploited ordepleted and the remaining quarter under- or moderatelyexploited. In India, recent stock assessment of exploitedfisheries indicated a number of fish stocks are exploited closeto MSY level, some overexploited and some underexploited(Srinath 2003; Srinath and Balan, 2003; Pillai, 2006). Furtherresearch is needed to be more specific in this classification.Reports all over the world indicate that the fallacy, ‘alwaysthere are more fish in the sea’, has ended. Most of the world’sexploited species are not being assessed or managed and MSYcannot be estimated with much precision in many fisheries


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(Mohan Joseph & Jayaprakash, 2003). For developingmeaningful strategies for conservation of pelagic fisheries,there is need to critically examine the biological attributesof the fishes and the socio-economic aspects of fisheries thatrender them vulnerable.

With the open access system in operation for thepast 60 years in India, exploited marine fisheries in thecoastal area almost reached a peak of production (Dehadrai& Yadava, 2004). Research indicated further increase infishing intensity would not increase fish productionsubstantially in the presently exploited region up to about100m depth, except for some marginal increases in certainpockets and from a few underexploited resources. Since thecoastal fisheries sector has been beset with all types ofnecessary evils of indiscriminate fishing, habitat degradation,pollution, sectoral conflicts, declining catches anddeteriorating socio-economic conditions of fishermen andlocal communities, the situation calls for urgent managementmeasures and conservation strategies to maintain thesustainability of fisheries resources. A few significantstrategies are outlined below:

A. Effects of fishingi. Control of fishing intensity: It is not only the fishing

methods but the intensity of the fishing which has beencausing the decline in catches. The excess fleet sizeshave to be reduced and regulated. The resources ofeach region have to be matched with the sizes of fleetsof each method of fishing.

ii. Halting of destructive gear: Certain fishing gears likethe purse-seines, ring seines, the disco-nets and othersimilar gears, though very effective and productive,have been found to be destructive at least in the coastalareas. Spawning schools of fish and small sized fishare often caught indiscriminately in such gears, whichreflect on future catches. Stricter control on the seasonsand areas of operation and the mesh sizes of such netsis essential. Use of dynamites and blast fishing shouldbe totally prohibited.

iii. Regulation of mesh sizes: The mesh sizes of variousfishing nets have scientifically been fixed not toendanger the resources but hardly enforced. There isno alternative to this, if sustainability is to be ensured.Creation of awareness about the damage to resourcesamongst fishers is a top priority.

iv. Monitoring of targeted species: For reasons of highavailability, easy capture, quality and consumerdemand, certain species may be intensely andcontinuously exploited. Both artisanal and industrialfisheries can cause population declines in such fishes.Pelagic schooling fishes are quite vulnerable forcapture when spawning and feeding schools areencountered. Adverse environmental conditionscombined with mass capture of fishes like the oil

sardine, mackerel, Bombay-duck, ribbonfishes,carangids, whitebaits, other clupeids and tuna can alsolead to diminishing catches. Added to this, young onesof targeted species could be the components of by-catchin other small meshed fishing gears. Habitatdegradation of nursery areas of some species and ofother species of limited distribution like the coral reeffishes may enhance the damage to stocks. Hencecontinuous monitoring and regulation of targetedspecies stocks is one method of conservation.

v. Capture of non-targeted species: In the non-selectivefishing gears, several species and their young ones areoften captured in considerable quantities. Trawls,encircling nets, hooks and lines and traps contribute tosuch catches. Such species are simply discardedbecause they are of low value. There is need to conservesuch species, especially their young stages, byregulating fishing effort, places of capture and seasons.

vi. Control on trawling: Though the trawl fishing in thecountry has emerged as the most effective fishingmethod, the damage it caused to fish resources and thesea bottom habitat, benthic fauna and biodiversity ingeneral cannot be denied. Seasonal and non-uniformbans on trawl fishing in different parts of the countryare enforced but the results have not been convincing.Further effective controls are required for conservingthe resources as well as for protecting the coastal,highly productive benthic habitat. Trawl fishing holidayfor two to three years, designation of no-trawling areasbased on scientific study and complete diversificationof trawling vessels to other methods of fishing seemto be the only alternatives to retrieve the deterioratingconditions of resources and the habitat.

vii. Saving juveniles and young fishes from capture: Thisis a very sensitive measure of conservation of fisheriesresources. It is quite evident that future resources areat a stake because of the capture of young stages offish which would otherwise attain large sizes, livelonger and contribute to increased catches. Several non-selective gears are responsible for such destruction.Market-driven forces, especially for small shrimp, alsoencourage such capture. The mesh sizes of such netshave to be increased depending on the type of speciescaught. The only solution is to strictly enforce meshregulations as per scientific recommendations and alsoban operation of some of the gears especially targetingyoung ones. Fisheries extension has to play a key roleto educate fishers on conservation of young fishes.Young ones of several pelagic species are captured insuch gears at present.

viii. Retrieval of discards: Several species of fishes of lowvalue are discarded at sea or at the fish landing centres.Other edible and non-edible species which are crucialfor biodiversity are also discarded or destroyed. This


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again is a result of operation of non-selective gears.Several regional estimations of discards have beenconducted which indicate loss of huge quantities offish and other biota. Methods recommended foravoiding such wastages have to be adopted.

B. Biological attributesi. Protection to spawners: Several spawning stocks–

of pelagic fishes are often captured in differenttypes of nets, especially when they move in largeschools. Some rationality in such capture has to beexercised to ensure future production. It is possible toconserve such resources when the congregations arelimited to specific areas and seasons. More research atsea is needed to generate specific data and informationand also continuous monitoring of spawningaggregations.

ii. Damage to critical nursery and spawning habitats: Theestuarine and nearshore habitats like the salt marshes,mangroves, seagrass beds, coral reefs and lagoonsconstitute important nursery grounds for several speciesof fishes. The coastal productive grounds afford ampleforage to young fishes. Antrhopogenic disturbances tosuch areas can cause great harm to fish resources.Available protective measures have to be enforced.

iii. High fecundity of pelagic fishes: Though this could bea contrivance provided by nature to offset high naturalmortalities in the early life histories of several pelagicfishes, research indicated the declines in populationsdo not bounce back to original state of the populationsdespite high potential to do so. Therefore, continuousmonitoring of spawning stocks, eggs and larvae at seafor delimitation of areas is essential to conserve suchvulnerable stocks both from fishing and adverseenvironmental conditions.

iv. Critical stages in the life-histories: Different stages inthe life-histories of fishes are vulnerable to naturalmortalities as well as fishing mortalities. Though it isdifficult to identify such stages, ages, sexes and habitatsfor various species, at least in conspicuous cases,conservatory measures can be taken by restrictingfishing in nursery areas or where spawning adultsabound.

v. Catchability of schools of fishes: Schools of fishes arehighly vulnerable to capture. It is profitable to capturethem even when they are at low population level.Further research on schooling fishing is needed toconserve their stocks at sustainable levels.

vi. Precautionary principle and reference points: Forconserving the fishery resources, adoption ofprecautionary principle and reference points would berequired to consider uncertainties in production,population sizes and mortality rates which are not tobe exceeded or desirable to maintain.

C. Ecosystem approachi. Ecosystem impacts: Exploited species of fishes are

initimately connected to trophic cycles and behaviourcontrolled by environmental conditions. Competitionfor food, predation at various levels and pollution ofcoastal waters determine the abundance of fishpopulations. Plankton feeding fishes occupy niches infood webs that are critical for production. Therefore,monitoring trophic cycles at sea would yield valuableinformation on the fluctuations in abundance of fishesfor which suitable models can be developed.

ii. Marine reserves: Research indicates marine reservesserve the purpose of protection and conservation ofresources, biodiversity and habitat improvement. Theeffectiveness of the existing marine reserves in thecountry should be reviewed for their role inconservation of fish resources.

D. Implementation of regulatory measuresNational and State legislations are available in the form

of Indian Fisheries Act 1897, the Wildlife Protection Act1972, MFR (regulation) Bill 1978 formulated after the EEZdeclaration, MFRA of maritime states enacted in 1980,Maritime Zones of India Act 1981, Environment (Protection)Act 1986 etc., for safeguarding the fisheries resources.Regulatory measures include enforcement of closed seasons,closed fishing areas and periods, ban on certain destructivefishing gears and methods, minimum mesh size regulationand minimum legal size at capture. Better management andconservation of fisheries resources and protection of aquatichabitats would, however, depend on how effectively theabove regulations are enforced.

CONCLUSION

For achieving the goals of conservation of fisheriesresources in general and secure the future of exploitedfisheries, there is need for reducing fishing effort, applicationof precautionary principle and reference points, ecosystembased fishing, work at sea on spawning aggregations, eggsand larval surveys, onboard vessel work on the detectionand quantitative estimation on schools of fish as done in theerstwhile Pelagic Fisheries Project off the west coast of India,identification of critical life stages, establishment of effectivemarine reserves and implementation of regulatory measures.

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46

Prawns and shrimps comprise about 2500 speciesdistributed throughout the world. They belong to complextaxonomic groups. Extensive studies on the taxonomy andbiodiversity of palaemonid prawns of the world have beencarried out by many (Chace & Bruce, 1993; Holthuis, 1950;1952; Jayachandran, 2001a, for review).

Our knowledge on the Indian palaemonid decapodcrustaceans are mainly from the research work of AnanthaRaman et al (1978), Bate (1868), Chopra & Tiwari (1949),Dutt & Ravindranath (1974), Holthuis (1950), Jalihal et al.(1988), Jayachandran (1987- 2007), Jayachandran & Joseph(1982-1992 a-b), Jayachandran & Raji (2004 a-b),Jayachandran et al. (2003; 2007), Kemp (1913-1925), Nobili,(1903), Sankolli & Shenoy (1979), Tiwari (1947–1963),Tiwari & Pillai (1973). These studies have recorded 75species of inland prawns. The present paper provides acomprehensive account on various aspects such as diversityof species, state wise distribution of species, taxonomic statusand confusion, molecular taxonomy, karyologicalinformation, distribution based on their habitat, present levelof utilization of diversity, research challenges and also exsitu and in situ conservation methods and needs ofpalaemonid prawns of India.

MATERIALS AND METHODS

The present study has been made based on the research


Indian palaemonid decapod crustaceans : taxonomic status, researchchallenges and conservation needs

K V JAYACHANDRAN

College of Fisheries, Kerala Agricultural University, Panangad P O, Cochin, Kerala 682 506

ABSTRACT

Prawns and shrimps comprise about 2500 species and are distributed throughout the world. They belong to complextaxonomic groups. The prawns of the family Palaemonidae Rafinesque, 1815 are highly important on both commercialas well as ecological point of view. Extensive studies on the biodiversity and taxonomy of Indian freshwater prawnshave been carried out by many and they have recorded 75 species belonging to 8 genera under the subfamily PalaemoninaeRafinesque, 1815 and these prawns inhabit a wide range of habitats from hill top to estuaries. The present paper providesa comprehensive account on various aspects such as diversity of species, state wise distribution of species, taxonomicstatus and confusion, molecular taxonomy, karyological information, distribution based on their habitat, present levelof utilization of diversity, research challenges and also ex situ and in situ conservation methods and needs of palaemonidprawns of India.

Key words: Biodiversity, Decapoda, Distribution, Palaemonidae, Utilization

work of Kemp (1913–1925), Tiwari (1947–1963), Tiwari &Pillai (1973), Dutt & Ravindranath (1974), Sankolli &Shenoy (1979), Jalihal et al. (1988), Jayachandran (1987–2007), Jayachandran & Joseph (1982–1992 a–b),Jayachandran & Raji (2004 a-b), Muphy & Austin (2005),Jayachandran et al. (2003 – 2007), Min-Yun Liu et al. (2007).

RESULTS AND DISCUSSION

Diversity of Indian Palaemonid DecapodsThe family Palaemonidae is a large complex group of

prawns. So far 96 genera and more than 720 valid specieshave been recorded under this family. They belong to twosubfamilies, namely, Palaemoninae Rafinesque, 1815 andPontoniinae Kingsley, 1878. The prawns belonging to formersubfamily inhabit inland water bodies and the latter in themarine habitats.

Genera and species under the subfamily PalaemoninaeRafinesque, 1815More than 300 species under 21 genera have been

described under this taxon.

GeneraOut of the 21 genera reported so far under the subfamily,

8 genera have been found to represent India comprising of 75species (Table 1) and are grouped according to habitats. Thedifferent species in different Indian states are given in Table2. The rivers in Kerala, have a rich resource of 30 species.([email protected])

April 2010] INDIAN PALAEMONID DECAPOD CRUSTACEANS 47

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Table 1. Genera and species under subfamily Palaeninae

Sl. No. Genus Species No. of species

1 Allobrachium Jayachandran, -2001@

2 Exopalaemon Holthuis, 1950 styliferus (H. Milne Edwards, 1840)* 1

3 Leandrites Holthuis, 1950 celebensis (De Man, 1881)* 1

4 Leptocarpus Holthuis, 1950 fluminicola (Kemp, 1917)* 3potamiscus (Kemp, 1917)*kempi Jayachandran, 1992*

5 Macrobrachium Bate, 1868 aemulum (Nobili, 1906) *** altifrons altifrons (Henderson, 1893) 59*****altifrons ranjhai Tiwari, 1963 *****andamanicum (Tiwari, 1952)*assamense assamense (Tiwari, 1955) *****assamense peninsularae(Tiwari, 1955) *****australe (Guerin-Meneville, 1838) **banjarae(Tiwari, 1958) ***birmanicum (Schenkel, 1902) ***bombayenseAlmelkar & Sankolli, 2007canarae (Tiwari, 1958) *** cavernicola(Kemp, 1924) ******dayanum (Henderson, 1893) *** divakaraniJayachandran, 2001 *elatum Jayachandran.1989 *equidens (Dana, 1852)*gangenticum Bate, 1868 **gurudeve Jayachandran & Raji, 2004*****hendersodayanum (Tiwari, 1952) ****hendersoni hendersoni(De Man, 1906) ****hendersoni cacharense (Tiwari, 1952) ****hendersoni platyrostre (Tiwari, 1952) ****honnaense Thampy,Jayachandran & Arunachalam, 2007 ***** idae (Heller, 1862)**idella idella (Hilgendorf, 1898) **idella georgii Jayachandran& Joseph, 1985 **indicum Jayachandran & Joseph, 1986 *****javanicum (Heller, 1862) **jayasreei Jayachandran & Joseph,1985 *****johnsoni Ravindranath, 1979 **josephi Jayachandran, 2001**kempi (Tiwari, 1952) ***kistnense (Tiwari, 1952) ***kulkarniiAlmelkar & Sankolli, 2007kulsiense Jayachandran, Lal Mohan & Raji,2007 **kunjuramani Jayachandran & Joseph, 1985 *****lamarrei lamarrei(H. Milne Edwards, 1837)**lamarrei lamarroides (Tiwari, 1952)****lar Fabricius, 1798*latimanus (von Martens, 1868) *****malcolmsonii(H. Milne Edwards, 1844) **manipurense (Tiwari, 1952) ***mirabile(Kemp, 1917) **naso (Kemp, 1918) ***nobilii (Henderson &Matthai, 1910) ***novaehollandiae (De Man, 1908) *ornatusJayachandran & Raji, 2004 ***peguense (Tiwari, 1952) ***rogersi(Tiwari, 1952) ***rosenbergii (De Man,1879) **rude (Heller, 1862)*sankolli Jalihal & Shenoy, 1988scabriculum (Heller, 1862) **siwalikense (Tiwari, 1952) ***sulcatus (Henderson & Matthai, 1910)*tiwarii Jalihal, Sankolli & Shenoy, 1988unicarnatakae Jalihal, Sankolli &Shenoy, 1988veliense Jayachandran & Joseph, 1985 *villosimanus(Tiwari, 1947)***

6 Nematopalaemon Holthuis, 1950 tenuipes (Henderson, 1893)*karnafuliensis (Khan, Fincham & Mahmood, 21980)*

7 Palaemon Weber, 1795 concinnus Dana, 1852*belindae (Kemp. 1925)*debilis Dana,1852*pacificus (Stimpson, 1860)*semmelinki (De Man, 1881)*serrifer (Stimpson, 1860)*sewelli (Kemp, 1925)*

8 Troglindicus Sankolli & phreaticus Sankolli & Shenoy, 1979****** 1Shenoy, 1979

9 Urocaridella Borradaile, 1915 urocaridella (Holthuis, 1950)# 1

48 JAYACHANDRAN [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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Table 2. State-wise distribution of species under the subfamily Palaemoninae

States Species reported from India

No. Names of species

Andhra Pradesh 10 M. rosenbergii M. malcolmsonii, M. idella, M. rude, M. equidens, M. scabriculum, M. dayanum,M. nobilii, M. johnsoni P. concinnus,

Arunachal Pradesh 2 M. dayanum, M. hendersoni hendersoni

Assam 9 M. rosenbergii, M. cavernicola, M. hendersoni, M. altifrons altifrons, M. assamense assamense,M. gangenticum, M. birmanicum, M. hendersoni hendersoni, M. hendersoni cacharense

Bihar 5 M. lamarrei lamarrei, M. malcolmsonii, M. altifrons altifrons, M. gangeticum, M. birmanicum,

Chattisgarh 1 M. dayanum,

Goa 4 M. idella idella,M. equidens P. sewelli, P. pacificus,

Gujarat 1 M. malcolmsonii

Haryana 2 M. altifrons altifrons, M. siwalikense,

Himachal Pradesh 1 M. dayanum,

Jharkhand 1 M. dayanum

Jammu & Kashmir 2 M. dayanum (?), M. siwalikense,

Karnataka 13 M. rosenbergii, M. lamarrei lamarrei, M. idae, M. idella idella, M. equidens, M. scabriculum,M. hendersodayanum, M. kistnense, M. canarae, M. sankolli, M. unikarnatakae, M. tiwarii,M. banjarae,

Kerala 30 M. rosenbergii, M. aemulum, M. idae, M. idella idella, M. idella georgii, M. indicum, M.rude, M. novaehollandiae, M. equidens, M. sulcatus, M. latimanus, M. scabriculum, M.divakarani, M. elatum, M. josephi, M. canarae, M. sankolli, M. veliense, M. gurudeve, M.jayasreei, M. kunjuramani, P. pacificus, P. belindae, E. styliferus, L. potamiscus, L. fluminicola,L. kempi, L. celebensis,

Madhya Pradesh 5 M. assamense peninsularae, M. banjarae, M.kistnense, M. malcolmsonii, M. assamensepeninsularae

Maharashtra 15 M. rosenbergii, M. lamarrei lamarrei, M. idella idella, M. equidens, M. scabriculum, M.kistnense, M. hendersodayanum, M. malcolmsonii, M. bombayense, M. kulkarni, P. serrifer,E. styliferus, L. potamiscus, N. tenuipes, T. phreaticus,

Manipur 4 M. lamarrei lamarrei, M. lamarrei lamarroides, M. dayanum, M. manipurense

Meghalaya 2 M. dayanum, M. rogersi

Mizoram 1 M. dayanum

Nagaland 1 M. dayanum (?)

Orissa 10 M. rosenbergii, M. lamarrei lamarrei, M. rude, M. equidens, M. scabriculum, M. dayanum,M. nobilii, M. malcolmsonii, E. styliferus, U. urocaridella

Punjab 3 M. siwalikense, M. dayanum, M. malcolmsonii

Rajasthan 1 M. lamarrei lamarrei

Sikkim 0

Tamil Nadu 14 M. rosenbergii, M. lamarrei lamarrei, M. malcolmsonii, M. aemulum, M. idae, M. idellaidella, M. rude, M. latimanus, M. scabriculum, M. peguense, M. nbobilii, P. pacificus, P.belindae, N. tenuipes,

Tripura 4 M. rosenbergii, M. malcolmsonii, M. scabriculum, M. kempi,

Uttarkhand 1 M. dayanum

Uttar Pradesh 6 M. altifrons altifrons, M. gangeticum, M. kulsiense, M. kistnense, M. birmanicum, M. assamensepeninsularae

West Bengal 17 M. rosenbergii, M. lamarrei lamarrei, M. rude, M. equidens, M. mirabile, M./scabriculum,M. assamense assamense, M. birmanicum, M. lar, M. javanicum, M. placidulum (?), M.villosimanus, M. kempi, E. styliferus, L. fluminicola, N. tenuipes, N. karnafuliensis

Andaman & Nicobar Islands 6 M. australe, M. andamanicum, M. lar, M. latidactylus, P. debilis, U. urocaridella


49

State wise distribution of species under the subfamilyPalaemoninaeThe available information on the state wise distribution

of prawns is given below which indicates the lacuna on thisaspect (Table 2).

Taxonomic ambiguitiesThe genus Macrobrachium contains more than 200 valid

species. Since this genus contains too many species with widerange of variations there were attempts to separate the speciesand placed under two or more taxa. A new genusAllobrachium was proposed by Jayachandran (2001) toaccommodate around 30 species which are at present treatedunder the genus Macrobrachium. However, this wasdisagreed by Min-Yun Liu et al. 2007. Similarly many speciespossess characters which are narrow for elevation to specieslevel.

Molecular TaxonomyThe chromosomal information of palaemonid prawns are

limited to a few species only (M. idella, M. nipponense, M.rosenbergii, M. scabriculum, M. siwalikense, M. superbum,M. lamarrei lamarrei) (Jayachandran, 2006 for review).

Some studies have established that barcode regions of COIhas considerable potential as the foundation for a DNAbarcoding identification system for crustaceans (Costa et al.,2007). Murphy et al. (2005) have analysed 16S rRNAsequences from 30 species of Macrobrachium forestablishing phylogenetic relations.

The author also has done some studies in penaeid prawnsand similar studies have been undertaken at College ofFisheries, KAU, Cochin on Macrobrachium. The collegewelcomes associations of institutions in this regard for similarstudies. It is absolutely essential for establishing the speciesand phylogetic status of highly complicated group ofpalaemonid prawns.

Evidences for GondwanaJayachandran and Joseph (1988; 1992a) provided new

evidences in support of Gondwana land.

Grouping of prawns on the basis of habitatThe prawns of the subfamily Palaemoninae can be

categorized into the following groups based on their habitatpreferences* Prawns living and completing their larval life cycle

in saline water.** Prawns living in upper regions of estuaries and/or

lower stretches of rivers with or without tidalinfluence, but completing their larval life cycle insaline water.

*** Prawns living in freshwater and with or withoutestuarine larval phase.

**** Prawns living in interior water logged areas (ponds

and lakes) with limited distribution and completeslarval life cycle in freshwater.

***** Prawns living in hill streams without down streambreeding migration and abbreviated larvaldevelopment.

****** Prawns living in caves or subterranean life# Marine.

Present Utilization of the resourcesAt present the resources are utilized in the following ways:

Species of capture importanceA few species are reported to be commercially important

in different states of India. These prawns are either marketedlocally or exported. M. rosenbergii, M. malcolmsonii, M.gangeticum, M. idella idella, M. idella georgii, M. divakarani,M. equidens, M. sulcatus, M. dayanum, M. lamarrei lamarrei,M. lamarrei lamarroides, M. mirabile, M. scabriculum, M.rude, M. villosimanus belong to such group. Catch data formost of the states and water bodies are lacking.

Vembanad Lake is the natural abode for M. rosenbergii.Catch data of the species collected from the lake for the years– 1997 to 2004 is given below.

Year Landings (kg)

1997 186 6851999 330 0952000 390 4442001 490 7482002 489 5022003 232 9292004 266 068

It is disappointing to note that during the peak breedingseason (June to December) nearly 40% to 60% of the catchconstituted berried females. This single factor is the majorthreat to the wild population of the species in the lake.Personal observation is that the population size of the lake isdwindling alarmingly and the present catch revival reportswere mainly due to the artificial stocking of hatcheryproduced seeds by Government agencies. Conservationmeasures are discussed elsewhere.

Species of Aquaculture importance : Though the speciesdiversity of the genus is rich, only a few species are at presentutilized for aquaculture production. The species ofimportance include: M. rosenbergii, M. malcolmsonii, M.gangeticum. Mass larval production attempts were successfulto an extent with regard to these species.

There are different types of aquaculture practices goingon in Kerala, namely, monoculture, polyculture, integratedculture of freshwater prawns. Of these special mention hasto be made about Paddy cum prawn culture (‘Oru Nellumoru Meenum’ – in Malayalam or One rice – One fishprogramme). This programme was developed by Kumarakom


50

Research Station, Kerala Agricultural University(Padmakumar, 2006). He has designated it as the win – winLand Use model. In this system the rice and fish are grownalternatively or in sequence. Joseph (2003) also revealed thatyield and returns (per ha) in Paddy-prawn rotational farmingsystem is highly profitable (cost : benefit ratio is 1.46).

The advantages of this system are:a. It enriches the soil, thus increases the rice production.b. It helps to control insect pests and aquatic weeds.c. Large areas of paddy fields utilizing for such fish

culture do not demand any major modifications in itsnatural physiography.

d. Such fields are more suitable for rice farming.e. Such fields are ecological harmonious.f. More productive and profitable than popular crop

rotations.h. Generates employment opportunities.Species having aquaculture potential, but unutilized: M.

josephi, M. villosimanus, M. latimanus are potential specieswhich can be utilized for aquaculture because they grow tobigger size. Practically very little information is availableon various aspects of biology and management of thesespecies.

In addition to the above species, there are a few specieswhich are to be considered for ecosystem based as well ascultivation at rural areas. M. idella, M. dayanum, M. equidens,M. sulcatus, M. rude are medium sized species to beconsidered in this respect. M. idella for example establishesitself in the freshwater as well as low saline areas withoutany intervention from man. Therefore management of suchspecies is important for augmenting production in rural areas.One advantage of this method is that production can beachieved without altering the prevailing ecology. This speciesis quite acceptable to people. To mention an example forthis is China’s cultivation of M. nipponense, a lesser sizedspecies of high acceptance.

Species with ornamental value : Recently Jayachandran(2006 a; b; 2007) and Jayachandran et al. (2006) have madepioneering attempt to introduce 8 species of ornamentalprawns of the genus Macrobrachium to the aquarium (Figs.1-11). This is the first step in this direction. The species ofornamental value include – M. canarae, M. latimanus, M.ornatus, M. gurudeve, M. rosenbergii, M. kulsiense, M.assamense, M. rogersi and M. sulcatus. This is a novelmethod of utilization of biodiversity, but judiciousexploitation from the wild is necessary for which regulatorymeasures are to be urgently taken up to protect them fromover exploitation. This programme will certainly improvethe livelihood security of rural people. Not much work hasbeen carried out in these lines.

A new concept in Aquaculture: Cultivation of lesserspecies along with M. rosenbergii, M. malcolmsonii, M.gangeticum etc. proved beneficial. The lesser species willact as forage. This is a novel approach of organic farming.

This is being practiced under the supervision of the author.The advantages of the present practice are; improved healthof cultivating species, reduction of disease problem in speciesunder cultivation and drastic reduction of feed inputs andmaintenance of good water quality.

Value addition: College of Fisheries, K A U has attemptedto develop a number of products utilizing the lesser speciesof Macrobrachium. The products developed are PrawnPickle, prawn cutlet, prawn stick (Pavunny et al., 2007). Theother products that can be produced include – flavour extractand chitin and chitosan production from shell waste.

Research ChallengesAs per account given above, it is very clear that only a

few biological studies have been undertaken on majority ofspecies and hence information is available about them isscanty. For the successful management of this highly valuableresource, it is essential to concentrate on research on thefollowing aspects. College of Fisheries, KAU, Cochinextends their willingness to associate in these lines.

a. State-wise/wet land wise prawn genetic resource ofIndia has to be ascertained.

b. Biological studies such as the role played by eachspecies in maintaining micro-climatic conditions,breeding nature, interrelationship with co-habitantshave to be undertaken.

c. Prawns are basically scavengers/detritivores. But thereare smaller sized species which consume periphytonand algae. Research should be oriented in thesedirections.

d. Judicious exploitation of resources should be enforced.e. Utilization of diversity of prawns for non-edible

purposes like ornamental use, as forage etc. has to beworked out

f. DNA Barcoding, 16S rRNA sequencing are to beundertaken. Some studies are going on at the Collegeof Fisheries, KAU.

g. Ethno-zoological information on prawns should beundertaken and patented under IPR.

h. Karyotyping of prawns necessary for hybridizationprogrammes for the production of new varieties

i. Background information and policy formulation fortransplanting species out of natural habitat is essentiallyrequired and worked out.

Conservation NeedsDue to habitat deterioration of wet lands population size

of many species are reported to be on the decline. Commercialspecies like M. rosenbergii, M. malcolmsonii, M. gangeticumare over exploited. Many species are already under threat ofextinction. An emerging area of biodiversity utilization isornamental trade of freshwater prawns. Already there areexports of prawns from the wild without knowing to whichspecies they belong. Considering all the factors there is a need


51

to develop a country status of freshwater prawns and initiateaction plans for in-situ and ex-situ conservation for theprioritized species based on the evaluation of threatenedspecies.

Some of the conservation efforts carried out for M.latimanus by College of Fisheries, KAU include:

a. Collecting young and juveniles from the hilly regionswhich are under the threat of drying up during summermonths. These were grown under captivity to theberried condition and subsequently released them backat the spot from where they were captured.

b. Collecting berried females and young ones which arelocked up in endangered temporary pools and pondsformed in hill streams and released in the streams soas to save the prawns due the conditions during summermonths.

c. Producing larvae under captive conditions andreleasing them back to the spot where mother prawnswere captured.

ACKNOWLEDGEMENTS

The author is thankful to Dr. W. S. Lakra, Director,NBFGR, Lucknow and other distinguished members of theorganizing committee of the National Conference on AquaticGenetic Resources and to the Dean, College of Fisheries,KAU, Cochin for giving the opportunity to present this paperand to Dr. Anil Kumar, M P E D A, for providing me withsome specimens from North India.

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Jayachandran K V. 1992. Redescription of Macrobrachium lamarreilamarroides (Tiwari) with a note on M. lamarrei lamarrei (H.Milne Edwards) (Palaemonidae). Mahasagar 25 (1) : 19–24.

Jayachandran K V. 1992. On the genus Leptocarpus Holthuis, 1950,with the description of a new species (Decapoda, Palaemonidae).Mahasagar 25 (2): 129–34.

Jayachandran K V. 2001. Palaemonid prawns Biodiversity,Taxonomy, Biology and Management. Science Publishers, inc.,Enfield (NH), USA; Plymouth, UK, 624 p + Preliminary pages(International Edition).

Jayachandran K V. 2001a. Taxonomic status of Macrobrachiumbirmanicum (Schenkel) and M. choprai (Tiwari) with a note onclosely related species. Indian Journal of Fisheries 45 (3) : 345–48.

Jayachandran K V. 2003. Fishery resources on the Western Ghats.Natural Resource Management : Changing Scenarios andShifting Paradigms, College of Forestry, KAU 20–9.

Jayachandran K V. 2003. Freshwater prawn diversity of India andadjacent countries. Proc. National symposium of ZoologicalSociety of India 154–63.

Jayachandran K V. 2004. Biodiversity of palaemonid prawns ofIndia. Silver Jubilee Souvenir: 100–02.

Jayachandran K V. 2005. Inland fishes and fisheries of Kerala State.Status paper. Proc. State Biodiversity Strategy and Action Plan(SBSAP) for Kerala, prepared under The National BiodiversityStrategy and Action Plan (NBSAP) – India, Kerala ForestResearch Institute 134–44.

Jayachandran K V. 2005. Biodiversity of palaemonid prawns ofIndian seas. CMFRI Bulletin 84: 21–8. (article in HINDI)

Jayachandran K V. 2005. Diversity of Palaemonid prawns of theHimalayan Region. Proc. Natl. Symp. On Status of Cold Waterfisheries with reference to fragile Himalayan Aquatic Ecosystem(Prof. M.K. Jyoti et al.,) 157–65.

Jayachandran K V. 2006. Chromosome Numbers in Crustacea, AReview. Advances in Environmental Science & Technology 97–107.

Jayachandran K V. 2006a. Freshwater prawns of ornamental valuefrom Kerala. Training Manual on Ornamental Fish Culture 96–98 + a colour plate.

Jayachandran K V. 2006b. Why not prawns and shrimps inaquariua?. Proceedings. Aqua ornamentals–2006: 19–22.

Jayachandran K V. 2007. Ornamental Freshwater prawns In:Ornamental Fish Breeding, Farming and Trade (Kurup B M,Boopendranath M R, Ravindran K, Saira Banu and Nair A G.(eds.)), Dept. of Fisheries, Govt. of Kerala, India : 99–106.

Jayachandran K V and Joseph N I. 1982. Record of the largestsized Macrobrachium rosenbergii (de Man) (Decapoda,Palaemonidae) from Kerala Waters. Journal of Inland FisheriesSociety of India 14: 86–7.


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Jayachandran K V and Joseph N I. 1985. A new species ofMacrobrachium from the south–west coast of India (Decapoda,Palaemonidae). Journal of Natural History 19: 185–90.

Jayachandran K V and Joseph N I. 1985. On a new subspecies ofMacrobrachium idella (Decapoda, Palaemonidae) from thesouth-west coast of India. Aquatic Biology V: 130–34.

Jayachandran K V and Joseph N I. 1985. Allometric studies inMacrobrachium scabriculum (Heller, 1862). Proceedings of theIndian National Science Academy, B 51 (5): 550–54.

Jayachandran K V and Joseph N I. 1986. On a new species ofMacrobrachium (Palaemonidae) from south-west coast of India.Crustaceana 50 (2): 217–24.

Jayachandran K V and Joseph N I. 1988. Length-weightrelationships of two palaemonid prawns, Macrobrachium idellaand M. scabriculum, A comparative study. Fishery Technology25 (2): 92–4.

Jayachandran K V and Joseph N I. 1988. Two new records of thepalaemonid prawns from Indian waters. Fishery Technology 25(2): 95–9.

Jayachandran K V and Joseph N I. 1989. Palaemonid prawnresources on the south-west coast of India. Journal ofAquaculture in the Tropics 4: 65–76.

Jayachandran K V and Joseph N I. 1989. Resources, ecobiology,taxonomy and distribution and proximate composition of thepalaemonid prawns of the south-west coast of India. Proc. FirstKerala Science Congress, Cochin, organized by StateCommittee on Science, Technology and Environment,Government of Kerala 108–14.

Jayachandran K V and Joseph N I. 1992. On a new record andredescription of Macrobrachium novaehollandiae from IndianWaters (Decapoda, Palaemonidae). Records of the ZoologicalSurvey of India 91 (3–4): 475–79.

Jayachandran K V and Joseph N I. 1992. A key for the fieldidentification of commercially important Macrobrachium spp.of India with a review of their bionomics In: Silas E.G. (ed)Freshwater prawns. Kerala Agricultural University 72–7.

Jayachandran K V and Raji A V. 2004. An ornate new species ofMacrobrachium Bate, 1868. from Kerala, India. Journal ofInland Fisheries Society of India 23: 41–4 (figs. 2).

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Jayachandran K V, Raji A V and Sally Simon. 2003. On theindiscriminate capture of Macrobrachium rosenbergii (De man,1879) from the Vembanad Lake and suggestions for theirconservation. In : Freshwater Prawns : Advances in Biology,Aquaculture and Marketing 745–47.

Jayachandran K V, Raji A V and Tessa Thomas. 2006. Prawns andshrimps of ornamental value from Kerala. Proc. Recent Trendsin Mariculture : 77–9 (+1 colour plate).

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Joseph K J. 2003. Coastal economy of Kerala : a profile. KeralaAgricultural University, Thrissur, p 40.

Kemp S. 1913. Crustacea Decapoda. Zoological results of the ArborExpedition 1911–12. No. 20. Records of the IIndian Museum 8:289–310

Kemp S. 1915. Crustacea Decapoda. Fauna of Chilka Lake.Memoirs of the Indian Mueum 5: 199–325.

Kemp S. 1917. Leander styliferus Milne Edwards, and relatedforms. Notes on Crustacea Decapoda in the Indian Museum,IX. Records of the Indian Museum 13: 203–31.

Kemp S. 1918. Crustacea Decapoda of the Inle Lake basin. Recordsof the Indian Museum 14: 81–102.

Kemp S. 1922. Pontoniinae. Notes on Crustacea Decapoda of theIndian Museum, XV. Records of the Indian Museum 24: 113–288.

Kemp S. 1925. On various Caridea. Notes on Crustacea Decapodain the Indian Museum, XVII. Records of the Indian Museum27: 249–343.

Min-Yun Liu, Yi-Xiong Cai and Chyng-Shyan Tzeng. 2007.Molecular systematics of freshwater genus MacrobrachiumBate, 1868 (Crustacea, Decapoda, Palaemonidae) inferred frommtDNA sequences, with emphasis on East Asian species.Zoological Studies 46 (3): 272–89.

Murphy P N and Austin C M. 2005. Phylogentic relationships ofthe globally distributed freshwater prawn genus Macrobrachium(Crustacea: Decapoda : Palaemonidae): biogeography,taxonomy and the convergent evolution of abbreviated larvaldevelopment. Zoo Scripta 34 (2): 187–97.

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Tiwari K K. 1955. New species and subspecies of Indian freshwaterprawns. Records Indian Museum 53: 297–300.

Tiwari K K. 1961. Occurrence of the freshwater prawnMacrobrachium latimanus (Von Martens) in India and Ceylon.Crustaceana 3 (2): 98–104.

Tiwari K K. 1963. A note on the freshwater prawn, Macrobrachiumaltifrons (Henderson, 1893). Proceedings Zoological Society,Calcutta 16 (2): 225–38.

Tiwari K K and Pillai R S. 1973. Shrimps of the genusMacrobrachium Bate, 1868 (Crustacea : Decapoda : Caridea :Palaemonidae) from Andaman and Nicobar Islands. Journal ofthe Zoological Society of India 25 (1 & 2): 1–35.

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Corals belong to the phylum Anthozoa and they are objectsof beauty and utility. The hermatypic corals with theirsymbiotic zoothanllae build the mighty reefs beneath thewaves that are exposed only at low tides. Corals areexclusively marine and taxonomically belong to the orderscleratinia.

They are both solitary and colonial, the solitary forms arecalled ahermatypes and they do not have symbionts. Reefbuilding corals grow actively in the photic zone of the ocean.Coral reefs are found in the tropical waters as a belt aroundthe globe.

The reefs of seas around indiaIndia has a coast line of nearly 8000 km but the reef

formation is restricted to four major centres, viz. Gulf ofkutchh. Gulf of Mannar, Lakshadweep and Andaman andNicobar Islands. Lakshadweep is exclusively atolls but othershave fringing reefs or patch reefs. Barrier reefs are found inAndamans. Additionally the Malvan area and Kanyakumaridistrict of Tamil nadu have patchy reefs. The vast stretch ofBay of Bengal except for Andaman and Nicobar Islands isdevoid of any coral formation. Estimation of reef flats ofIndian reefs by remote sensing has shown that the extent ofthe area in Gulf of Kutchh is 148.4 km2 that of Tamil Naducoast as 64.9 km2. Lakshadweep 140.1 km2 and that ofAndaman and Nicobar Islands 813.2 km2. Additionally knollsand lagoon reefs from roughly 50 km2. (Pillai, 1996).

Morphology of indian reefsZonation is not distinct in certain areas as in Palk Bay.

However, two major morphologically distinct types occur.Reef flats and lagoon shoals dominated by ramose orbranching corals. The dominant genera include Acropora,Montipora and llopora. Intermittent with these are foundmassive and encrusting genera like Porites and faviids. The


A review of the status of corals and coral reefs of India

C S GOPINADHA PILLAI

Central Marine Fisheries Research Institute, Kochi

ABSTRACT

Precise estimation of the biodiversity of corals from any area is subject to variation due to uncertainty of synonymy.Corals exhibit very high intraspecific skeletal variation depending on the physiographic and hydrographic condition.The present paper describes overview of coral resources in Indian seas, their biology and taxonomy, anthropogenicstress on coral reefs, conservation and research efforts being put by various organisations.

Key words: Corals, Coral reefs, India, Oceans

second physiographically demarcated area comprisesmassive corals that form the chief frame work of the reefs.The dominant genera include Porites, Favia, Favites,Goniastrea, Platygyra and Cyphastrea. In Lakshadweep thelagoon reef flats have extensive coverage of Heliopora.Gorgonids are scarce in the shallow waters of our reefs thoughthey are present in deep waters from where they are collectedfor export. The soft corals or alcyonarians are dominantamong the hard corals in Andaman and Nicobar Islands andthey do occur in Gulf of mannar and Gulf of Kutchh.

The coral fauna of indiaPrecise estimation of the biodiversity of corals from any

area is subject to variation due to uncertainty of synonymy.Corals exibit very high intraspecific skeletal variationdepending on the physiographic and hydrographic condition.Estimation of the variation of skeletal morphology is oftendifficult and this has resulted in the duplication of manyspecies. The studies on the taxonomy of Indian corals have ahistory of nearly 160 years starting with Link (1847) fromNicrobar Islands. Subsequent studied by British scientistson material housed in Brithish Musem Natural History,London and works of Late Prof. George Matthai and C.S.G.Pillai have elucidated the coral fauna to some extent. Pillaiestimated the coral fauna of Gulf of Mannar and Palk Bay(1972/1886) Lakshadweep Gulf of Kutchh (Pillai and Patel1988) Andamans (Pillai 1993) westcoast of India i.e. theerstwhile Travancore coast including the Kanyakumari coast(Pillai and Jasmin) for details of references the recent workof George and Sandhya (2007) may be referred along withPillai (1986). Pillai (1996) published a detailed status reporton the corals and coral reefs of India which still remains tobe the basic document though subsequently status reportswere prepared and published by several authors includingWilkinson (2000), Muley et.al. (2002) and Patterson et. al.

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(2007). Pillai (1996) listed 199 species of corals from Indianwaters of 71 genera of which 55 were hermatypes and therest ahermatypes. The Colonial or hermatypes comprised 155species and the rest deep sea or shallow water ahermatypes.Since that publication taxonomic work on Andaman andNicobar Islands by Venktaraman et. al. (2002) ZologicalSurvey of India, Gulf of Mannar from George and Sandhyaand Patterson yielded a few more speices. Venkataraman et.al.2002 lists 208 hermatypes from India. Additional informationbased on recent works from Marine biosphere in Gulf ofMannar accounts for nearly 8 more species, thus totalling toabout 220 species (subject to further taxonomic) of colonialcorals plus nearly 45 species of deep water and shallow waterahermatypes. This total accounts for about 265 species ofstony corals from our waters there to known. However,Vankataraman and other states that another 111 species ofhermatypes are reported from Anadamans by underwaterdiving and this should be added to the list. The species listedby SCUBA diving on more sights, the records are unreliablesince identification of corals in-situ underwater with anycertainty is difficult. Wells as early as 1954 stated thatapproximately 700 species of corals occur in the whole ofIndo-Pacific. However, this is also is not final, for severalauthors since have, especially the Australian workers addedmany more species so also the scientists of Philippines tothe biodiversity of Indo-Pacific corals. If one takes John Wells1954 estimate of 700 species along with additionalinformation provided by recent workers the total will be about775 species. This indicates that circa 35% of the Indopacificcorals occur in our waters since Pillai’s work on Lakshadweepand Gulf of Kutchh no intensive survey in those areas hasbeen done especially the deep waters facies. In essence toget a realistic picture of our coral resources we have to domore collection, collation literature survey settling of thesynonymy and the like. This is to be done by a team of expertscientists, SCUBA divers and technical persons who arededicated to their assigned task.

The living resources of reefs of indiaThe waters around the reefs are reported to be nutritionally

poor. Despite this reefs harbour a rich fauna and flora. Outof the 34 marine genera 32 are reported to occur in reef asparabion, crypobion, borers and free living. The exact numberof species living on a reef from any area is yet to be preciselyestimated. The determination of biodiversity on a reefdepends on the exact number occurring, the area covered,the time spent on collection and seasonal variation. Thebiodiversity of reef associated organisms in Indian reefs isstill to be critically assessed.

The dominant flora comprises, Gracilaria, Gelidiella,Hypnea, Sarconema, Hydrodathrus, Cauleropa, Sargassumand Turbinaria. The marior sea grasses include Thalassiahemprichi, Halodule univervis cymodocea serrulata,Syringodium sp. and Enhalus acroroides. These are found

on the reef flats and lagoon shoals.The reef associated fauna constitute, sponges both boring

and free living, other coelenterates, such as hydroides,alcyonarians gorgonids and sea anemones. Many areas onIndo-Pacific reefs are rich in hydroid corals such as millepore,Heliopora and Distichopora and black or thorny corals. Thecrustacean fauna is immensely rich. The global estimate ofcrustaceans is about 150,000. It is reported that Indian watersharbour nearly 3000 species. The exact number of reefdwelling crustaceans that are important and are exported fromIndia is yet to be determined.

The molluscs are a dominant component of reef dwellinganimals. The global estimate of molluscan species is aroundone lakh fifty thousand. About 5000 species occur in ourwaters. Several bivalves cause bio-erosion to dead and livingcorals. Several gastropods such as Trochus, Turbo, cowriesand many others are exploited from the reef for variousproposes. A cottage industry in south India exists onmulluscan shells.

The echinoderm fauna of India is estimated to the tune of760 species and many are found on reef. Some likeAcanthaster planci are predators of corals and occasionallyin many parts of the Indo-Pacific this species increase inlarge numbers causing sever damage to the living corals.

The bryozoans are tiny colonial coelomates encrustingon corals and about 200 species occur in our waters. Theexact numbers of reef dwelling species are yet to be known.

Reef fishes are rich in number and species. Lakshadweepis reported to have about 600 species of reef fishes andAndaman and Nicobar Islands also have nearly 600 species.Reef fishes are both resident and migrant. Seasonal variationin species composition is often seen in a reef track. Reeficthyofauna is highly colourful and form valuable aquariumsamples. They are often highly priced.

The reptilian fauna is essentially constituted by turtles.They are a protected class of animals.

Anthropogenic and natural threats to indian reefsCorals and coral reefs all over the tropical waters are under

stress due to various anthropogenic and natural intervention.The interference of these factors on Indian reefs has beenreported by several workers (Wells, 1988, Pillai, 1996;Venkataraman, 2002, Wilkimson, 2000, Patterson, et.al,2007). The major natural causes for the destruction of coralsinclude siltation, cyclone, local tectonic upheavals, tsunami,pests and predators and EI Nino. During 1988 a notable risein surface water temperature was observed and large scalemortality to corals was reported as a result of 1997/98 ElNino southern oscillation. Venkateraman (2000) reports thatthis has affected reefs in Gulf of Mannar and many speciesof corals were bleached. However subsequent studies byPatterson (loc. cit.) show that the southern part of Gulf ofManner has densely populated reefs and there is no sign ofimpact of El Nino event.

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Coral diseasesCorals are also affected by various fungal and bacterial

diseases. In Gulf of manner and Lakshadweep three types ofdisease have been recorded in the recent past, viz. white banddiseases, black band disease and bacterial/fungal infection.The exact cause of this being studied by various institution.Venkataraman (2000) states that it is stress related.

Silt and sedimentation cause asfixia on polyps and coralsdie. Sea erosion, dredging the reef environs, deforestationand construction activities stir up silt and sediment. Pestsand predators also cause death of corals. Among the predatorsthe echinoderm acanthaster planci is the most disastrous.This is reported from Lakshadweep and Andamans. Thepopulation of the starfish in Lakshadweep is normal and isdoing little harm. There was a great increase of the starfishin Andamans but the damage was minimum. The star fishfeed on coral polyps leaving the skeleton white.

Bio-closion is the reef go hand in hand with reef buildingmolluscs, polychaetes and echiuroid are the major bioerodingagents on a reef.

Blasting of the reef is a human activity that causedestruction to reefs. In the post independent yearsintroduction of mechanized fishing crafts resulted in theblasting of the reefs to deepen the boat channel inLakshadweep. Quarring of corals for various industrialpurposes and construction work in Gulf of Mannar resultedin the total lose of fringing reefs in some islands. Dredgingthe lagoon for navigational purposes degraded the atoll reefsof Lakshadweep. Only in some part of Nicobor Islands andAndamans undisturbed reefs remain.

Management issuesAs already indicated, our reefs are under severe ressure

from many reasons. This valuable natural gift is almostirreparably exploited. Coral reefs and corals protect the coastfrom wave action. The value of reefs is both extractive andnon extractive. The extractive values include many foodorganisms including fishes, molluscs and crustaceans. Pearloysters are normally found in the reef environs. Corals aretraditionally used for medicine. The reef associated organismsprovide raw material for many life saving drugs and reefs arepotential areas for pharmacological research. The geneticstructure of reef corals is little investigated and it is of greatvalue in the determination of species. They have decorativevalue. They provide raw material for lime, cement and calciumcarbonate since the skeleton of corals contain 98.5% purecalcium carbonate. They are building blocks for houses inatolls and coastal areas. The non-extractive use of coral reefsis chiefly tourism. They are excellent sites for scientificresearch. Tourists are mainly attracted to the reef for skin andSCUBA diving and sport fishing. Though, the tourism is yetto fully develop. Due to the above mentioned value of the reefsthey have to be protected and conserved for the futuregeneration. Development and conservation rarely go hand in

hand. Hence we have to utilise reefs on a sustainable level andas such management strategies have to be taken up.

Action taken for conservation of reefs in indiaNeed for conservation of coral reefs is evident from the

value of this marine benthic, tropical community. Thoughreefs were present and mankind utilized their resources fromtime immemorial a greater awareness for the conservationand protection emerged only in the later half of the lastcentury. Early workers in the 19th century did not much arguefor protection to reefs, for reefs survived in healthy condition.But indiscriminate exploitation and unhealthy interferenceon reefs by man made them threatened ecosystem andecologists and naturalists started pointed out to the necessityfor reef conservation. India had the privilege to hoist thefirst International symposium on corals under the auspicesof the Marine Biological association of India in January 1969where in reef scientists from 11 countries participated. Aninternational committee for the conduct of further symposiain every 4 years was also constituted. And to date 10 symposiawere conducted in various tropical countries. However, ourinvolvement in the series of meetings later was virtually nill.

Efforts in India for conservation of reefsRealising the needs for the protection of this valuable

marine resource the Government of India has taken steps toconserve and manage the reefs from early 1986. A nationalcommittee on corals and mangrove was constituted by theMinistry of Evironment and forests and expert scientists,administrative staff and state govt. officials wereincorporated. The mandate of this committee was to advisethe govt. on strategies of protection and conservation of thereefs, in addition to eco-development and awareness creationon island population and coastal dwelling people on the needfor conservation. A research committee was also constitutedwith a view to recommending need based research projectsto scientific institutions and non-governmental agencies.State level steering committees were also constituted to oversee the progress of implementation of management actionplans. Thrust areas were identified. Marine parks andbiosphere reserves were established. The Gulf of KutchhMarine Park, in Gujarat, Mahatma Ghandi Marine Park inWandoor S. Andamans, Gulf of Mannar Biosphere and JhansiRani Marine Park in Andaman and Nicobar were establishedNodal institutions in these areas were indentified to carryout research and monitoring. Research projects were fundedNon-governmental organisations of repute were encouragedto persue research and to ensure awareness creation on theprotection of reefs.

LegislationThe Govt. of India has promulgated various legislations

covering coral reef conservation. The wild life protectionact 1972 provides protection to certain marine species. Efforts

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are being made to bring corals under this act. The Governmentof India issued a Coastal Regulation Zone notification in 1991and amendments in subsequent years. The collection of coralseither dead or live is strictly prohibited except for scientificresearch by identified institutions. All scleractinians andgorgonids are brought under wild Life Protection Act. 1972from July 2001.

Thought India gave a fillip to reef research by organisingthe first International symposium on coral reefs, in 1969,subsequent involvement of our country in furthering researchin this filed is limited.However, to supplement national effortsrelated to conservation and management of coral reefs andassociated living resources the Ministry and environment andForests, Government of India has been collaborating throughsome international initiatives in this country. Under theUNDP/GEF programme studies have been undertaken inGulf of Mannar through MS Swaminathan ResearchFoundation. Another project in Andaman and Nicobar Islandshas been completed. The ultimate aim of these studies is toevolve a viable Management action plan on Indian coral reefs.The management of coral reefs is currently vested with theforest officials. Marine biodiversity management and eco-development needs trained personals other than forestofficials. With the collaboration of Australia India has trainedthree scientists in Australia on coral taxonomy with a viewto capacity building to strengthen reef research the Ministryof Environment has initiated action for the establishment ofa National Institute of Coral Reef research at Port Blair. Thisis currently associated with the Zoological Survey of Indiaand a small laboratory with limited staff is established.

On going research activitiesZoological Survey of India, National Institute of

Oceanography and Central Marine Fisheries ResearchInstitute are the major national centres of current reefresearch. The Suganthi Devadason Marine Research Instituteat Tuticorin Tamil Nadu is a private organization that is veryactively engaged in reef research in Gulf of mannar. Themajor ongoing research activities at various centres aremainly on various aspects covering Biodiversity of coralfauna; Biophysical monitoring of reefs; Reef restoration andcoral transplantation; Reproductive biology of corals; Studieson the physical and biological impact on reefs GIS basedmapping of reefs; Livelihood programmes on coastalpopulation to reduce anthropogenic pressure; Awarenesscreation on the value of reefs and need for conservation;Capacity building in the taxonomy of corals and reef dwellingorganisms to assess biodiversity.

Current reef research and achievementsThe knowledge of scleractinian corals has considerably

increased. All the major reefs are reasonably studied.Formulation and partial implementation of conservation lawshave considerably reduced the distruction of reefs. An attemptis made to capacity building in various sectors includingtraining to coral taxonomists.

Tourism is restricted to selected areas. Effluent dischargeto reefs has been considerably controlled. Continuousmonitoring of the reefs in Gulf of Mannar and some parts ofA&N Islands and Lakshadweep enabled us to understandpresent status of reefs so also recolonisation of scleractionsafter mortality. Awareness to the value of reefs and need forconservation of this ecosystem has increased particularlyamong the coastal people and Island inhabitants. Someattempts are being made to transplant corals for eco-development Marine Parks and biosphere established.

Suggestions for future researchTaxonomic studies on reefs should be carried out.

Maritime universities and research institutes should beencouraged to take up further reef research for whichinfrastructure is to be developed. Pharmacological researchof marine organisms may be taken up on a priority ground.Eco tourism and eco development should receive attention.Continuous monitoring of the reefs may be made to assessvarious impacts thus to implement remedial measures.

REFERENCES

George Rany Mary and Sandhya Sukumaran. 2007. A systematicappraisal of head corals (Family Acroporidae) from the Gulf ofMannar Biosphere South-east India. Bull.cent mar. fish Res. Inst50: 118

Patterson J K Edward et al. 2007. Coral reefs of Gulf of MannarSoutheastern India, distribution diversity and Status, CORDIOSuganthi devadason Res. Inst.m pp. 113.

Pillay C S G. 1983 The coral environs of Andaman and Nicobarislands with a checklist of species. Bull.Cent.Mar. Fish.Res. Inst34: 33–43

Pillay C S G. 1986 Recent corals from the South-east coast of India.In: P.S.B.R.James (ed.) Recent Advances in Marine Biology.Today and Tomorrow Printers and Publishers, New Delhi; 107–201.

Pillay C S G and M I Patil. 1988 Seleaesimain Corals from Gulf ofCutch. J.Mar.Biol.Ass. India 30: 54–74.

Pillai C S G. 1996. Coral reefs of India: Their conservationand management. In: Marine Biodiversity conservationand Management (Ed. Menon N G and Pillai C S G). CMFRIpp. 16–31.

Pillai C S G. 2002. Biodiversity of reef building corals of India.Dept. of Biotechnolgoy. Govt. of India (Under publication).

Venkitaraman et al. 2002. Hand book on hard corals. ZSI. Calcutta.pp. 266.

Wilkinson Clive. 2002. Status of coral reefs of the world GCRMN.Aust. Inst Mar. Sci pp. 363.

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Marine resources of islands: status and approaches for sustainable exploitation/conservation with special emphasis to Andaman and Nicobar

S. DAM ROY and GRINSON GEORGE

Fisheries Science Division, CARI, Port Blair

ABSTRACT

Island ecosystem is unique but with a great diversity. Marine resource potential of Andaman and Nicobar Islands(ANI) is underutilized. The sensitive ecosystems of corals and Mangroves are facing threats as a result of changingclimate. Potential fishery resources need to be exploited in sustainable manner for income and employment generationof islanders. Primary data on resources of Bay Islands are collected resorting to standard survey methods and secondarydata are used as supporting data for analyzing the trend and potential of fisheries in ANI. The paper is depicting indetails the major marine resources and their status in Bay Islands and approaches for their sustainable exploitation andconservation.

Key words: Andaman and Nicobar islands, Conservation, Marine resourses

The Andaman and Nicobar Islands fall under the Agro-ecological region 21 (Hot humid to per humid Island eco-region). The Islands have a true maritime climate with leastvariation in maximum and minimum temperaturesthroughout the year. A plenty of (about 1530 mm) rainwaterfrom middle of May to middle of December and a deficit ofabout 610 mm is experienced during remaining part of theyear. On an average the Islands received around 3100 mmrainfall with considerable fluctuations in annual rainfall withhighest being experienced in 1961 (4300 mm) and the lowestin 1979 (1550 mm). The Administration of Andaman andNicobar Islands have demarcated nine fishing zones fororganized fishing in these Islands. Some of the importantspecies as per their landings are of sardines, perches, silverbellies, carangids, mackerel, seer fish, mullets, prawns andother crustaceans. About 19 species of penaeid prawnsbelonging to six genera and 6 species of lobsters also occurhere. Among the molluscs, the most important are Trochus,Turbo shells, Pearl oysters, Giant clams, mussels and oysters.Freshwater fishes like Catla, Rohu and Mrigal are also beingcultivated in ponds. In general, the annual landings throughcapture fisheries in these Islands have increased gradually.as it is evident in Table 1, gear wise landing from 1993 to2002 is given in Table 2.

Island Fisheries are important in the National perspective.The projected potential of Andaman and Nicobar Islands is1.48 lakh tones. Out of this, the oceanic fisheries constitutesabout 60,000 tonnes of which tuna constitutes 46,700 tonnes,i.e. 77.83% of the oceanic fisheries. Out of the projected,

potential hardly 19% are presently utilized. The economicdevelopment of the Island, therefore, hinges on thedevelopment of tuna fisheries of the island and by optimallyutilizing available water for coastal aquaculture and opensea mariculture. Infrastructure such as harbour, cold storageand processing facilities as well as vessels/fleet composingof long liners are required. Since, the islands are laggingbehind in comparison to other similar development areas,there is need for putting these islands in a speedy developmenttrack in the initial planning period and keep up the tempo inthe subsequent plan periods with self generated support andsustainability. The farming and fisher families in Andamanand Nicobar Islands need special attention, includingtechnology training, techno infrastructure and trade. Islandfisheries have the problem of transport costs, particularly inthe case of perishable commodities which may be sold inthe mainland or neighbouring countries. Value addition Chainis therefore very important in context of Development of theIslands. The Andaman and Nicobar Islands and Lakshadweepgroup of Islands offer a great potential for improving theincome of the fisher folk as well as the entrepreneurs relatedto Fisheries Industries. There is considerable scope forimproving the income of fisher families on environmentallysustainable basis by introducing Integrated Coastal ZoneManagement and Scientific fish rearing, harvesting and fishprocessing.

ANDFISH – a road map for the development of fisheriesin A & N Islands’ was prepared for these Islands to expounda document for fisheries development keeping in view thepotential of the resources, the livelihood and employmentopportunities of the stakeholders, post-tsunami and theEmail: [email protected]

58 ROY AND GEORGE [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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current trends in global fisheries development. There are stillmore concepts and ideas in black and white to beimplemented in Island Fisheries development. PotentialFishing Zone (PFZ), a concept developed by SpaceApplication Centre, Ahmedabad and operationalised byIndian National Centre for Ocean Information Services(INCOIS) made inroads in all maritime states, but it has yetto make a break through in Bay Islands. This paper attemptsto address state of the fishery resources of the islandarchipelagos with special emphasis on Bay Islands.


Survey for monitoring the health status of coral reefs wasmade at sites –Mahatma Gandhi Marine National Park: JollyBuoy, Boat island and Tarmugli; Rani Jhansi Marine Nationalpark: people Deara, light house and jetty of Havelock island;North Bay, Phongi Balu and so on. Line Intercept transect(LIT) method was resorted. Observations with respect tohydrographical parameters, percentage cover of differentsubstrates including live corals, coral species composition

Table 1. Species-wise fish landings (in tonnes) of Andaman and Nicobar Islands.

Species 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Avg.

Anchovies 1260 1501 1382 1408 1395 1073 1361 1216 1105 1103 1280Barracuda 817 983 914 942 842 1022 1021 617 1489 946 959Belonidae 315 379 353 358 390 113 133 364 242 43 269Carangids 1299 1537 1455 1456 1350 1139 2249 1007 2144 3750 1739Catfish 528 665 590 560 540 431 388 510 321 170 470Chirocentridae 320 385 358 359 340 331 83 237 129 15 256Crabs 125 147 141 140 145 578 556 738 542 352 346Elasmobranchs 791 969 885 985 886 1157 941 1523 467 217 882Hilsa 1457 964 1630 1680 1580 729 478 416 159 228 932Mackeral 1393 1664 1559 1589 1430 1087 1213 1939 1512 2843 1623Miscellaneous 4154 3931 4655 4661 3998 3788 1996 2838 2838 2810 3567Mullets 804 1606 896 904 805 1262 1153 1417 1682 1043 1157Porches 1738 2155 1946 1951 1926 1482 3356 5636 7029 5330 3255Polynemids 226 274 209 218 209 201 430 62 17 20 187Pomfrets 306 393 342 393 345 472 499 1856 192 107 491Prawns 240 282 269 250 405 601 785 351 534 489 421Ribbon fish 422 496 473 481 395 597 527 424 253 97 417Sail & Sward fish 308 360 345 348 328 342 241 1307 316 82 398Sardines 2852 3296 3192 3214 3194 3926 5237 3823 2389 3048 3417Squids 186 235 253 253 249 276 82 86 41 64 173Seer fish 626 748 700 799 729 882 1172 1210 1019 1007 889Silver Bellies 1234 1446 1410 1420 1405 1090 1098 1557 1467 965 1309Thissocles 1064 1268 1191 1201 1118 2581 312 728 485 615 1056Tuna 869 1011 972 981 970 3823 1362 467 801 217 1147Total 23334 26695 26120 26551 24974 28983 26673 30339 27173 25561 26640

Table 2. Annual Gear-wise fish landings (in tonnes) of Andaman and Nicobar Islands

Species 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Avg.

Gill Net 9800 11212 10970 11045 10296 12557 7986 10391 9928 9875 10406Hook & Line 3267 3737 3657 3745 3641 7435 9464 8716 7215 6040 5692Cast Net 2567 3203 3134 3215 3125 3953 3678 5537 4026 2995 3543Shore Seine 4312 4805 4702 4795 4339 1935 1319 1629 2462 1611 3191Anchor or Stick 2100 2403 2351 2451 2325 2508 4162 2902 1925 2453 2558

NetTraditional 1260 1303 1254 1250 1200 451 8 5 54 805 759

MethodsTrolling 28 32 52 50 48 38 1062 735 744 279Disco Net - - - - - 96 48 58 733 1026 196Long line - - - - - - - 20 81 1 10Bow & Arrow - - - - - 10 8 19 14 11 6Total 23334 26695 26120 26551 24974 28983 26673 30339 27173 25561 26640

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and abundance of fish species and other associated faunawere recorded. Salient observations made in different zonesof selected coral reefs helped to identify the indicators thatgive information on health of reefs and to identify the reefsat risk. Secondary data were complied from the basic statisticspublished by Andaman and Nicobar Administration andbulletins of Fisheries Survey of India (basic statistics andFSI bulletins). Statistical analysis was done using MicrosoftExcel package. Several sittings of experts were held atdifferent occasions for discussing the policy level issues onAndaman Fisheries, which resulted in ANDFISH- a road mapon fisheries of Andaman and Nicobar Islands. Regular fieldsampling was done in cataloguing the checklist and data onmajor food fish groups available. A checklist on fishes ofAndamans published by CARI, Port Blair was referred forthe purpose. Strategic plans and infrastructure details areenumerated based on the technical expertise of the authorsin collaboration with the suggestions of various committeeswho implemented the fisheries policies of the islands.


Mangrove ecosystem: The Mangrove ecosystem of BayIslands is blessed with 25 true mangals and 93 mangroveassociates. (Dam Roy, 2003). The island topography is hillywith small tracts of coastal fallow lands. Average annualrainfall is around 3000 mm. The pH of the soil sampled variesbetween 3.5 and 6.5 and mostly acid sulphate soil. In surfacesoils, the bulk density varies from 1g/cm3 to 1.4 g/cm3.Organic carbon varies from 1.5% to 1.8%. The texture isclayey and rarely loamy and sandy. Though the content oforganic matter is high, the unbuffered cation exchangecapacity is low. There is a lot of water run off from the tropicalrain forest of Andaman and Nicobar islands, rich in organichumus that gets deposited as coastal sedimentation, makingcoastal lands rich in acid sulphate. Association of mangrovespecies likes Rhizophora and Nypa found in tidal brackishwater swamps is a strong indication of acid sulphate soils,while swamps with Avecennia are less acidic.

There is about 966 sq. km of mangrove area in Andaman& Nicobar Islands, with a variety of mangrove and associatedfauna, which are subjected to regular tidal inundation. In thepost tsunami scenario, in south Andaman alone, due to thesubduction of the land by about 1.25 m, the level ofsubmergence due to tidal influence has also increased. Asurvey conducted reveals that approximately 4000 ha areasof agricultural farmlands have been submerged, out of which630.12 ha of area are found suitable for coastal aquaculture.However, as coastal marshy wetlands are of acid sulphatenature, there have been a lot of apprehensions among theentrepreneurs, scientists, planners and administratorsregarding technical viability and success of these ventures.As per the available technology at present, these acidic soilscan be rapidly reclaimed with low cost technique. A feasibilitystudy conducted along the coastal marshy wetlands of South

Andaman explored this possibility. The ecology and scopefor fisheries in mangrove areas of ANI was explored in detail.The reduction in fish catch during 2004-2005 as revealed inthe basic statistics of Andaman & Nicobar Administrationmakes this study imperative as an alternate source of fish/shrimp production through coastal aquaculture.

Coral reef ecosystem: Coral Reefs of Andaman – a generalstatus assessment: Most of the coral reefs are of the fringingtype, colonizing nearer to the coastline on east and west coastsof Andaman. In-between the shore and the reef, the sea isnearly 40 m deep. The windward side slopes down suddenlyto a depth of 350–540 m and subjected to the monsoon winds.Channel reefs are found on the sheltered shoreline where thewater of the channel is relatively calm due to less wind andwave action. They are also known as leeward reef. Such reefsare located in Ritchie’s archipelago and South Andaman.Knolls occur in channels adjoining the fringing reef of theadjacent islands and may arise from about 20 m depths. Theyalso have flat tops. Porites and Favia are the chief reefbuilders in these types of reefs in the Andaman. On themargins of channels of Ritchie Archipelago occur the coralknolls built mainly by the above two species. The reef edgescontain mostly the stony corals of the genera Acropora,Pocillopora, Favia and Porites. At Rangat, the reef on theeast coast is thickly populated by massive corals, mainlyPorites lutea and on the sandy bottom by Pocillopora sppand Acropora spp. In long island about 72% of the bottom iscovered by massive type living corals. In Hut Bay, (LittleAndaman) dead coral colonies are observed. The cause ofdeath may be silt.

In the Andamans, the reef flat extends upto about 500 mfrom shore. Erosion channels upto 20m wide intersect theplatform. Reef edges support Acropora, Pocillopora, Poritesand Favia. On the west coast of South Andaman, extensivecoral reef formations were seen at Kurmadera and aroundthe islands of the Marine National Park off Wandoor. Thickestof fragile stag–horn coral (Acropora sp.) dominate in thatarea, providing shelter for several coral reef fishes.Undistributed extensive coral patches were seen around TwinIsland.

Management of coral reefs during stress conditions likemass bleaching is very important. One of the importantoutputs of studies of these islands is the observation madeon mass bleaching of corals and some associated fauna likesea anemone, giant clam; which harbour symbiotic algaewhich import colour to the host animals. In 1998 and 2005,NOAA as early as in February predicted that the surfaceseawater temperature would be increasing than normal duringthe year. Since, the seawater temperature is a critical factorfor the well-being of symbiotic association of host animalslike corals, giant clam; with micro algae they are harbouring,the impact of changes in temperature on coral reefs wasmonitored during the year. Out of several sites of coral reefssurveyed in South Andaman Islands, it was found mass


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bleaching of coral reefs started occurring from May 1998 to2005. The bleaching in corals was observed to range between2 and 39% and death in coral of especially branching typesto vary between 3 and 55.4% in various sites. The bleachingeffect continued up to July and later on the surviving coralsregained the health. The impact of elevation in surfaceseawater temperature affected reef flat zone. The massbleaching occurred due to the triggering mechanism ofelevation of temperature caused to extrude the symbioticalgae from host animal, which play key role in supplyingsynthesized food to the host corals to more than 90%. Massbleaching had changed coral reef community in a way, largelyeliminating branching corals and massive corals survivingand dominating.

Previous studies on Andaman corals reveals disease andstress induced mortality. The reasons of these incidents werenot catastrophic and the coral reefs recovered in time. Seriousconcerns were there about the health status of reefs asAndaman recorded an under sea earthquake of magnitude9.3 m in the Richer scale, that occurred on 26 December,2004 devastating many coastal habitats. The giant waveslashed along the coast refashioned the coastline devastatingtens of hundreds of hectares of mangrove forests. In protectedbays damages were less. Corals are very sensitive to theirambient water properties. Pristine transparent water inshallow protected bays ensures coral growth. So, a suddenmassive rushing in of water, its inundation, salinity changes,muddy and silt deposition made by retrieving water, joltscreated by the earthquake and the like were a major concernfor reef lovers. Corals were exposed after the earthquakeduring December, 2004 in Diglipur area. The continuousexposure led to the death of the corals, but those remained inthe submerged areas recovered.

Ornamental reef fishes: The marine ecosystem of A & NIslands offers a varied and complex flora and fauna of whichthe colorful coral reef fishes constitute the most fragile andinteresting faunal element. The fish fauna of ANI contributesmore than 1200 species of which over 250 species are ofornamental in nature. Inspite of huge potential of ornamentalfishes as a lucrative business opportunity in these islands,the culture and rearing of the same is yet to begin. Successfulbreeding and further standardization of breeding technologyof Amphiprion percula commonly known as clown fishesshow that sustainable and profitable production of marineornamental fishes can be taken up as an entrepreneurialventure in ANI with limited infrastructure facilities. Someof the most popular ornamental reef fishes are; Butterflyfishes, Angelfishes, Surgeonfishes, Wrasses, Squirrelfishes,Damsel fishes, Triggerfishes, Boxfishes and clownfishes.

Marine Food fishery: The fishery potential of ANI hasbeen estimated by various researchers (Jones and Banerjee,1972; Kumaran, 1973; Cushing, 1971; Antony Raja, 1980).The working group of revalidation of fishery potential hasaccepted the estimate made by Fishery Survey of India in

1990; according to which the pelagic resources potential (0-200 m) is 130,000 tonnes and demersal resource potential(0-50 m) is 22,500 tonnes. Harvestable oceanic tuna isestimated to be around 82000 tonnes. Therefore, a totalfishery potential of 2.345 lakhs tonnes exists in A & N EEZ.(Sudarsan et.al 1990). An analysis of the data on monthlyfish catch in ANI for 5 years during 1998 – 2002 reveals thatthere is no significant variation (P> 0.05) in the month-wisefish landings. However, in corporation of the average fishlandings in each month over 5 years, it has been observedthat Jan-Apr. is the peak fishing season with an average fishlanding of 2,659 tonnes while May- Aug. is the lean seasonwith an average fish landing of 1,925 tonnes.

There has been significant variation (P<0.01) in the annualfish catch and it rose to 33,339 tonnes (2000) from 23,334tonnes (1993). However, after 2000, the catch has declinedto a level of 25,561 tonnes during 2002. ANI account for <1% of the total marine fish landings of the country, thoughthe EEZ of the Islands is nearly 30% of Indian EEZ.Significant variation (P.0.05) has been observed in thelandings of different species of fishes. The landings ofSardines have been quite consistent and they account forabout 13% of the total fish landings has doubled (from8% to16%), when the fish landings during 1993–1997 and 1998–2002 are compared. Carangids, mackerel, silver bellies andanchovies altogether account for 22% of the total fishlandings.

The Sardines, Anchovies and Hilsa are caught by gillnets,boat seines and shore seines. The important genera areSardinella, Dussumieria, Pellona, Herkilotisicthys andAnadantostoma. Herkilotisicthys punctatus contributednearly 70% of the total sardine catch. The main season offishing is from July to December, Dorairaj and Soundararajan(1985). Among the anchovies Thryssa and Stolephorouscontributed to the major catch. The main season of fishing isfrom July to December. Two species of mackerels namelyRastrelliger kanagurta and brachysoma contributed to thefishery. The gears used are gillnets and boat seines and goodfishing seasons are March-June and September-December.

Hook and lines and gill nets mostly catch the perches.The important species belong to genera Lethrinus, Lates,Lutjanus, Pomadasys Epinephelus etc. The main fishingseason is from August to November. The carangids are landedby gillnets and boat seines and the major genera are Caranx,Selar, Chorinemus, Elegatus and Decapterus. The favourablefishing season is from July to November. Silver bellies aremostly caught in boat seines and shore seines and arerepresented by two genera, namely, Leiognathus and Gazza.The former accounting for more than 90%. The main seasonis from June to December. The mullets and barracudas arecaught by gillnets and boat seines and the peak season isfrom July to December. The main species of mullet are Mugilcephalus and Liza tade. The latter migrates along the tidesinto the creeks for foraging. Among the seerfish,

April 2010] MARINE RESOURCES OF ISLANDS 61

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Scomberomorus guttatus and S. commerssoni land in goodquantities. Sciaenids and catfish occur in trawl catches.

Tuna: The tuna and seer fish mainly caught in gillnetsand hook and lines during March–August. The peak seasonof fishing coincides with the pre-monsoon period. Duringsouthwest monsoon the fishery is at its lower ebbs. Theimportant tunas contributing to the fishery are little tuna(Euthynmus affinis) and skipjack, big eye, northern blue fin,little tuna, marlins, sailfish, sword fish etc. are reported tooccur in abundance especially around great Nicobar, southof Car Nicobar and southern regions. The potential stock oftunas in the EEZ of ANI is estimated to be around 100000tonnes (Sivaprakasam, 1979; John and Reddy (1989).According to fishery experts, stocks of 25000 tonnes ofyellowfin and big eye tunas and 50000 tonnes of skipjacktuna could be exploited (Abidi, 1979); Dorairaj andSoundararajan, 1985). However, the present exploitation oftuna is very meagre being around 600 tonnes constitutingabout 2.7% of the total fish landings. The Islands are, atpresent, thriving on a heavily subsidized economy. The percapita expenditure is the highest for the Islands whencompared at national level. However, the revenue generatedthrough tuna fishery development should provide enoughguarantees to offset the inflatory economy of the islands.The remoteness of the islands, lack of adequate infrastructurefacilities and poor knowledge of the spatial and seasonalabundance of tuna in the EEZ of A & N islands are the majorconstraints in developing a capital-intensive tuna fishingindustry (Soundararajan, 1996).

Elasmobranchs: The elasmobranches are generally caughtby gillnets and longlines, the sharks are mainly caught fortheir fins as exportable items. The species mainly belong toCarcharhinus, Scoliodon and Sphyrna. There has beensporadic fishery by one or two fishermen for deep-sea sharks.Centrophorus acus and Squatus megalops. They are caughtfor silver extraction (Soundararajan and Dam Roy, 2004).

Crustaceans: Among crustaceans, shrimps are mainlycaught using bagnets, boatseine, dragnets and castnets mostlyrelying on tidal cycles and lunar periods. Amongst prawns,Penaeus meguiensis (49%) and Metapenaeus dobsoni (42%)are dominant. Penaeus monodon, P.semisulcatus and M. ensisare caught in stray numbers in bottom set gillnets, which areoperated mainly for fishes. Six species of spiny lobster occurnamely Panulirus versicolor, P. ornatus, P. pencillatus, P.longiceps, P. homarus and P. polyphagus. Four species ofPortunid crabs namely Scylla serrata, Scylla tranqucharica,Portunus pelagicus and Portunus sanguinolentus are caughtby bottom set gillnets. Scylla serrata is also being caught inmarshy areas by putting hooks on crab holes.

Reef fishes: There is no real time assessment. However,based on a conservative estimate of average potential of about3 tonnes per km2 , it can be expected that about 3000 to 6000tonnes of reef fishes can be harvested from existing coralreef areas (Dam Roy et.al, 2001). Among the reef fishes,

perches and perch like fishes are represented by 7 majorgroups, like Lates sp. Serranus spp. Epinephelus spp.Polydaclyhus sp. Lettarimus spp., Pristipomoides sp. andPomadasys sp. The peak fishing season for these fishes isAugust to November.

Groupers: These form specially targeted group for exportas live fish. The annual potential of groupers, which formabout 10% of the reef fishes may be more than 300-600tonnes. It must be considered that the actual fishing area isvery much smaller at present in comparism to totalexploitable area and hence, the potential is far less leadingto over exploitation in limited areas.

Snappers and rabbit fish: These also have high exportvalue. Actual potential is not known but may be consideredat the same level of groupers. However, unlike groupers, theymove mostly in schools and hence, the exploitable biomassmay be higher (Dam Roy et al. 2001).Temporal Variation inCatches: An analysis of the data on monthly fish catch (Fig.1)in ANI for 5 years during 1998 – 2002 reveals that there isno significant variation (P> 0.05) in the month-wise fishlandings. However, in corporation of the average fishlandings in each month over 5 years, it has been observedthat Jan-Apr. is the peak fishing season with an average fishlanding of 2 659 tonnes while May- Aug. is the lean seasonwith an average fish landing of 1 925 tonnes.

Offshore Fisheries: There is no organized offshore fishingfrom Andaman base. However, the Fishery Survey of Indiais conducting systematic exploratory fishing, since October,1971. Bottom trawling, long lining, trolling, Kalava liningand purse seining has been conducted. Catch rates of as muchas 100 kg per hour obtained in Andaman waters arecomparable to those obtained in the east coast of India. Thedemersal fishes obtained by trawling are leiognathids (33%),upenids (19%), sciaenids (12%), skates (5%), rays (3.5%),shark (3%), nemipterides (3.5%), carangids (2.5%), catfish(2%), perches (1%), lizard fishes (0.8%) and othermiscellaneous fishes (Sivaprakasam 1979). Sudarsan (1978)stated that good catches of sharks and marlins were obtainedfrom long lining in areas south of North Andaman and castof Little Andaman including the Invisible banks. Duringsurveys, schools of sardine, mackerel, skip jack and othervarieties of tuna were also encountered in the Invisible bankswhich are located about 60 miles South of Port Blair andNorth East of Little Andaman. The period between Octoberand March is more productive than other period. Trollinglines, which were tried while proceeding to the fishing,ground and returning to the port during 1973–76 yieldedcatches upto 56 kg/hr. Carangids (28%), Tuna (17%) andPerches (4%) were the important fish groups caught bytrolling (Sundersan, 1978). Kalava lining operated during1974-75 could obtain highest catch of 18 kg/hr. perches(23%), sharks (15%), carangids (6%) and tunas (3%) werethe important fish groups caught. Purse seining was not highlysuccessful. Even though fish schools could be sighted they


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were not large enough. Further, the sizes of the vessel andthe net were not adequate for operating in deep waters(Sudersan 1978). Fishery Survey of India has beenconducting trials of tuna long-lining for sometime past andthe chartered vessels have also operated tuna long lines inthe past few years. Some useful information of the tunaspecies composition and the area of abundance have beencollected.

The oceanic location of A & N islands makes them idealfor the development of oceanic fisheries. The oceanic tunaresources, especially around the Bay islands are leastexploited since, India does not posses the required expertisein oceanic tuna fishery. The exploratory surveys conductedby the Government of India vessels have provided ampleevidence regarding the richness of tuna resources in the area.According to a working group (Anon, 1990), the estimatedpotential of tunas in the seas around the A & N islands is32000 in the coastal region and 94000 tonnes in the oceanicregion. The possible catch in the oceanic region by alonglining in 5000 tonnes and by surface netting is 121 000 tonnes.The introduction of pole and line fishery has limitation asknowledge of the availability of suitable baitfishes is limited.The strategy should be to develop deep water pole and liningin which fishing will be made for 4-5 days using largemechanized boats with facilities for holding baitfishes alivefor such duration. For assessing the actual potential for poleand line fishing, external expertise will be necessary fromregions like the Lakhsadweep or Maldives, where pole andline fishing has been specialized over the years.

Finally, the fishery development action plan should reckonwith the preservation of the pristine condition of the islandsto ensure the promotion of high-class tourism which is theother sector holding the key to the economic developmentof the islands.

REFERENCES

Abidi S A H. 1979. Sea wealth around us. The Andaman andNicobar Information, 1978–79, Port Blair. pp. 40–3.

Anon. 1969. Techno– economic survey of Andaman and NicobarIslands. National Council of Applied Economics Research, 1969.

Antony Raja B T. 1980. Current knowledge of fisheries resourcesin the shelf Area of the Bay of Bengal. WORKING PAPERS –BOBP/WP/8. pp. 24.

Arif M Musthafa, Chandrasekher J and S Dam Roy. 2001. Fish

and fisheries of exportable snappers (Lutjanidae), groupers(Serranidae) and emperors (Lethrinidae) from the westernfishing zone of South Andaman. Proceedings of the NationalSymposium on Biodiversity vis-à-vis resources exploration: Anintrospection. Journal of Andaman Science Association 17 (1,2): 236–48.

Cushing D H. 1971. Production in the Indian ocean and the transferfrom primary to secondary level. Biology of the Indian Ocean.B. .Zeitschel, (Ed) Springer-Verlag, Berlin. pp 475– 86.

Dam Roy S, Soundararajan R, Sarangi N, Varghese B,Chandrasekhar, Arif M Mustaffa and N Ram. 2001. Reef Fisheryresources of Andaman and Nicobar Islands and the scope oftheir sustainable exploitation. Journal of Andaman ScienceAssociation 17 (1, 2): 268–73

Dam Roy S. 2003. A Compendium on Mangrove Biodiversity ofAndaman and Nicobar Islands. pp 196.

Dorairaj K and Soundararajan R. 1985. Explained marine Fisheriesresources of Andaman and Nicobar Islands. Journal of AndamanScience Association I: 49–58.

John M E and K S N Reddy. 1984. Some considerations on thepopulation dynamics of yellow fin tuna, Thunnus albacares(Bonnaterre) in Indian seas. Studies on stock assessment inIndian waters. FSI Spl. Publn 2: 33–54.

Jones S and Banerjee S K. 1972. A review of the living resourcesof the Central Indian Ocean. Proc. Symp. on living resources ofthe seas around India. Marine Biological Association of India.pp. 1–17.

Kumaran M. 1973. The fishery potentials of Andaman and NicobarIslands. Proc.symp. on living resources of the seas around India.Marine Biological Association of India. pp. 387–89.

Sivaprakasam T E. 1979. The living resources of Andaman andNicobar seas. The Andaman and Nicobar information, 1978–79, Port Blair. pp 82–9.

Soundararajan R and S Dam Roy. 2004. Distributional record andbiological notes on two deep-sea sharks, Centrophorus acusGarman and Squalus megalops. (Macleay), from Andamanwaters. Journal of Marine Biological Association India 4 (2)pp. 178–84.

Soundarajan R. 1996. “Development of Tuna in the Exclusiveeconomic Zone of the Andaman and Nicobar Islands (India)” adissertation submitted to the Department of Marine Sciencesand Coastal Management. University of New Castle upon Tyne.pp. 237.

Sundersan. D. 1978. Results of exploratory survey around theAndaman Islands. Bull. Exp. Fish. Proj. 7 1–43.

Sudarsan D M, John M E and V S Somavanshi. 1990. Marine fisheryresource potential in the Indian Exclusive Economic Zone, Anupdate, Bulletin, Fisheries Survey of India 21: 20–2.

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In situ conservation and stock enhancement of endemic fish resources throughcaptive breeding and artificial sanctuaries

K G PADMAKUMAR1, L BINDU and P S MANU

Kerala Agricultural University, Regional Agricultural Research Station, Kumarakom

ABSTRACT

Pearlspot, Etroplus suratensis and Golden catfish Horabagrus brachysoma, are endemic to Peninsular India, facingserious depletion in the Vembanad wetlands due to environmental alterations. In order to develop viable breedingtechniques of these species under controlled conditions, habitat requirements and critical reproductive traits were closelymonitored. Both the species are omnivorous, the former is an asynchronous spawner while the latter a group synchronousspawner. Breeding behaviour of the species were closely observed in natural and experimental conditions and based onthis, captive breeding protocols were developed. E. suratensis was successfully bred under controlled conditions inartificial raceways of 70 m2. The percentage success of breeding in the devised system (71%) was higher than that ofpond breeding. Hatchling survival was also higher in the larval rearing system. Induced breeding of H. brachysoma wascarried out by the administration of Ovaprim @1ml. kg-1 body weight or fish pituitary extract @50-60 mg.kg-1 bodyweight, the former being more effective. Fertilisation upto 100% and hatching rate of 73.1% were obtained. The presentinvestigations on captive breeding is a major advance towards development of a standardized mechanism for conservationof indigenous species.

Key words: Captive breeding, Etroplus, Horabagrus, In situ conservation

The Western Ghat region in Kerala, on the south westcoast of India, covers over 42.5% of the entire Ghat region.Richly endowed with plentiful rainfall, and withprecipitation over 3000 mm per annum, the river network inthese places, results in near water logged conditions in almost20% of the total geographic area. The steep and undulatingtopography results in physiographic divisions, viz. thehighlands, midlands and lowlands, identified based on heightsabove mean sea level. The Western Ghat river system thusbecomes the biological hotspot, extremely rich in fishbiodiversity due to its unique topographical characteristics,altitude and depth gradient. The steep and short rivers changegradually from fast flowing highland streams to slowmeandering lowland rivers and generate habitats used bydiverse fish species and the biological diversity graduallyincreases downstream. The river systems that confluence ina continuous chain of backwaters of over 350 km and lieparallel to the coastline, also sustain very high biodiversityand exert profound influence on the coastal fisheries.

The Vembanad estuarine system, the floodplain wetlandsof five rivers, viz. Moovattupuzha, Meenachil, Manimala,Pamba and Achencoil in central Kerala, originating from theforested hills of Western Ghats, has been home to richbiodiversity. Although agriculture and fisheries have been

the two most important attributes of these wetlands; duringthe last century, the shallow flood plains and deltaic upperreaches of this wetland has been subjected to a series ofhuman interventions, all to facilitate and intensify ricefarming. The construction of a salt water regulator acrossthe estuary at Thanneermukkom, to check tidal ingressionof salinity in to the adjoining rice lands has been mostcatastrophic, as it affected the biological continuity of thelake. Its effect on the endemic fishery resources has also beenwidely documented (KWBS, 1989; Unnithan et al. 2001;Padmakumar et al. 2002).

Pearlspot, Etroplus suratensis, the commerciallyimportant omnivorous fish species in the lake, though tolerantto lower salinities is one such species that suffered rapidimpoverishment. This is attributed inter alia to large scalereclamation of shallow wetlands and destruction of thefringing vegetation and mangroves, that served as favorednursery areas of the species. Apart from this, their uniquebreeding behavior also impose severe constraints on theirnatural recruitment. Another fish species considered endemicto the Western Ghat region is Horabagrus brachysoma,popularly known as ‘Golden catfish’, or yellow catfish. Onceabundant in the lowland reaches of the riverine systems, thisspecies has also become an extreme rarity owing to illegalfishing practices, indiscriminate exploitation and destructionof natural habitats.Email: [email protected]

64 PADMAKUMAR ET AL. [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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Two main strategies for conservation of biodiversity insuch situations are (i) stock enhancement by conservationstocking and (ii) promotion of natural recruitment byestablishing protected breeding zones or sanctuaries. Thepresent study documents the development of captive breedingprotocols for mass production of seeds of E. suratensis andH. brachysoma, for species restoration and the establishmentof safe reproduction protection zone and sanctuary inVembanad for in situ conservation of E. suratensis.


A detailed survey on the fisheries production and exploitedresources of fish species of the wetland region wasundertaken during 1999–2001. The survey covered the entireflood plain riverine areas on the upstream portions of theVembanad lake south of Vaikom and the Thanneermukkombarrage (Fig. 1). The exploited catches of E. suratensis andH. brachysoma were assessed based on actual daily landingsregistered at thirty landing centers in the region. Thepredominant size groups of fishes in the collections andcommercial catches were analyzed. Experimental fishing wasconducted at different reaches using diverse gears, viz. castnets, gill nets, drag nets and other local fishing devices toelicit information on the changes in the population status,

seasonal distribution of juveniles and spawning adults in theflood plains.

Detailed investigations on feeding and breeding biologyof the two species, viz. E. suratensis and H. brachysomawere undertaken in order to identify the cues and triggersthat are necessary for successful reproduction andrecruitment. In addition to habitat requirement, criticalreproductive traits, viz. fecundity, Gonadosomatic index andgonadal changes etc., were also monitored. Breedingbehaviour of both species were closely observed in naturaland experimental conditions and based on their uniquebreeding attributes, hormonal and environmentalmanipulation protocols for captive breeding of each of thespecies were developed. H. brachysoma were subjected toinduced ovulation by using varying doses of inducing agentssuch as Carp Pituitary Extract (CPE) @ 50–60 mg.kg-1 bodyweight or synthetic hormonal analogues such as Ovaprim®@1ml.kg-1body weight, in single dose. For breeding of E.suratensis, artificial nesting substrates comprising woodenlogs fixed on to movable cement concrete base weredeposited as nest substrates. Breeding was successfullyaccomplished under controlled conditions using the attachedpairs. The nest containing the attached eggs were transferredto incubation tanks, provided with continuous aeration.Artificial breeding pits, fabricated on cement concrete, of 6cm diameter and 4 cm deep, were provided as larval habitatsduring hatchling nursing. In order to promote naturalrecruitment for conservation, an engineered breeding habitat/sanctuary of 25 acres was established in the open lake, atKumarakom on the eastern bank of the Vembanad lake. Whiledeveloping this, the habitat requirements of the species wereassessed very carefully and the situations were simulated.For this, a circular area of 10 ha in the open Vembanad lake,near Kumarakom was cordoned off, by planting coconut pilesand bamboo poles at close intervals to hinder fishing andobstruct operation of crafts and fishing gears. Artificial hillsand valleys were formed on the lake bed in the designatedsanctuary to facilitate substratum characteristics and depthsappropriate for natural breeding of the fish. Apart from this,a variety of artificial ‘nest’ and ‘reef’ substrates were installedon the lake floor to provide artificial nesting surfaces for thefish, as the fish is known to attach their eggs on underwatersubstrates at appropriate depths. Half split coconut shells,large boulders of laterite blocks, and specially designedcement concrete tetrapods were used as ‘paaru’ and ‘reefs’for simulated breeding. Additionally, fourteen mangroveislands were formed by fixing cement concrete rings andfilling them with excavated silt from the lake bed. Theseartificial mounts were planted with mangrove seedlings, anddeveloped as mangrove islands around the margin of thedesignated sanctuary. Extent of utilization of the protectedhabitats and deposited substrates in the sanctuary wascarefully evaluated through fish population census and visualcounts.Fig 1. Riverine stretches of Vembanad lake

April 2010] IN SITU CONSERVATION AND STOCK ENHANCEMENT OF ENDEMIC FISH RESOURCES 65

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The total annual fish production in the upstream locationsof the open lake was observed to be 440 and 434 tons,respectively, during 1999–2000 and 2000–2001. Although56 fish species were observed to inhabit the freshwater zones,thirty-six fish species were encountered in the commercialcatches. A comparison of the fish catches on either side ofthe salinity barrage revealed that the brackish water zone,immediately north of the barrage which accounts for only15.3%, contributed over 20% of the E. suratensis landings.

Captive breeding of Pearlspot, Etroplus suratensisThe indigenous cichlid, E. suratensis popularly known

as pearlspot, alone contributed to 200.6 tons per annum(46%). The catches were highest in the Kumarakom zone,constituting almost 48% of the total landings of this speciesin the lake (Fig.2, 3). A detailed evaluation of the productiontrend of pearlspot in the Kumarakom region for four years(2002–2005), revealed a perceptible reduction in productionand productivity, in terms of catch per unit effort (Fig.4).

Information on biological features is indispensable for

devising valid programs for conservation. Studies onbiological attributes of E. suratensis indicated that the fishprefers a herbivorous diet, comprising filamentous algae(43%), detrital matter (42%), macro-vegetation (12%) andmiscellaneous items (3%) comprising aquatic insects,molluscs (Fig.5.1). Fecundity of pearlspot was found to rangefrom 874 to 7554. Gonadosomatic index (G.S.I) for differentsize groups of females varied from 1.84 to 4.4. Highest G.S.Iwas observed during April and June coinciding with the pre-monsoon and monsoon season (Fig.5.2). Ova diametermeasurements indicated two distinct batches of eggs in thesame ovary (Fig.5.3) implying that the fish spawns twice ayear. The two G.S.I peak during March-April and June-Julyconform to this findings. The fish exhibited typical biparentalmonogamy and was found to form mating pairs close tobreeding and courtship commences only between such‘attached’ pairs. In nature, the paired fishes were observedto utilize stationary solid objects such as coconut leaves,coconut husk, wooden logs, stones and any other solidobjects, 11 to 45 cm above the ground. Both male and femalepartners were found to engage actively in nest preparation.After the substrates are cleared off, the female lay flat on thespawning site and gently move from end to end and attachtheir eggs carefully on to the nest substratum with the helpof its tubular and fleshy ovipositor. The male fish followclose behind and fertilize the deposited eggs instantly byreleasing a spray of milt. This process of egg laying andfertilization is continued several times and the eggs are seenplaced closely in a patch without touching each other. Thenumber of eggs per nest varied from 250 to 1573 with a meanof 854 and nest area per brood varied from 20 to 49.5 cm2

(Fig.6). After the eggs are laid, the female with their rhythmicfanning and mouthing activity, continually aerate the eggs;males guard the territory and chase away all intruders. Resultsof breeding trials is summarized in Table.1.

The very next day after egg fixing, the parent fish startedexcavating small cup like pits, on the ground, just below thenest, by scooping out mud and clean the vegetation aroundby vigorous mouth picking movements. The bottom pits

Fig 2. Catch variations of Etroplus suratensis in different zones

Fig 3. Exploited landings of Etroplus suratensis in Vembanad lake

Fig 4. Catch Per Unit Effort of Etroplus suratensis in scare linefishing.

0

50000

100000

150000

200000

250000

300000

Punnamada Kumarakom Thanneermukkom

Vaikom

2000–01

Catc

h(k

g)

Etroplus Total catch

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70

J F M A M J J A S O N D

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E.suratensis Total

Catc

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)

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30

35


Month

2003 2004 2005

CP

UE


66

Fig 5. Critical life history parameters of E.suratensis and H.brachysoma.5.1 Food composition—(a) Etroplus suratensis (b) Horabagrus brachysoma; 5.2 Gonadosomatic index—(a) Etroplus suratensis

(b) Horabagrus brachysoma; 5.3 Distribution pattern of eggs in a mature ovary—(a) Etroplus suratensis (b) Horabagrus brachysoma

9%

43%

1%

12%

35%

Diatoms

Filamentous algae

Molluscan shell

Macrovegetation

Detritus

Filamentous algae

Crustaceans

Fish offals

Macrovegetation

DetritusOthers

39%

6%22%

8%

23%

2%

0.00

0.50

1.00

1.50

2.00

2.50


Month

GS

I

0

5

10

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20

25

F F M A M J J A S O N D

Month

GS

I

0

10

20

30

40

50

60

0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75Ovadiameter (mm)

Fre

quency

(%)

0

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20

30

40

50

60

0.13 0.38 0.63 0.88 1.13 1.38 1.63

Ovadiameter (mm)

Fre

quency(%

)

5.1 (a)

5.2 (a)

5.3 (a)

5.1 (b)

5.2 (b)

5.3 (b)

varied in number from 7 to 15 (Table 2). Both the coupleparticipate in the process and males are more activelyinvolved in this laborious job. The eggs hatch out in 70–72hours and the hatchlings or ‘wrigglers’ are picked up by thebrooding female in its mouth and transferred to the breedingpits. The parent fish actively engages in ‘pit guarding’, abehaviour characteristic to this species. During this periodalso, fanning and mouthing of the brood is continued. Whenthe yolk attached to the hatchlings is fully utilized, in a week,the ‘wrigglers’ become free swimming and gradually move

out of the pits and swim freely in to the open waters escortedby the parents.

In the context that E. suratensis exhibited such acharacteristic parental behaviour, to facilitate captivebreeding, breeding situations were simulated in an artificialraceway system (70 m2). The raceway system consisted of ashallow cement tank with sloping floor that facilitated a mildflow of water and high transparency. The heavily yolkedhatchlings were found to congregate instinctively in theartificial pits placed in the larval rearing tank. Around 900–


67

1200 eggs were produced per brood and over 95% survivalwas obtained in the larval rearing system.

Captive breeding of Golden catfish, Horabagrus brachysomaThe survey revealed that H. brachysoma, once abundant

in these wetlands, constituted only 1 to 1.8% in the localfishery in the lake. Their incidence was more pronounced inriver systems confluent to the Vembanad lake. The fish wasobserved to inhabit dark locations adjacent to granite side-pitching areas of the irrigation canals and weed infestedshallow riverine locations, especially where submerged herbsof Aponogeton provide natural shelter habitats.

Studies on food and feeding revealed that the fishapparently feed on filamentous algae (39%) followed bydetritus (23%), fish offal (22%), macrovegetation (8%),crustaceans (6%) and other items (2%) (Fig.5.1b). The fishattains maturity during the first year of age and malesapparently mature earlier than females. Females exhibited agroup synchronous ovarian development (Fig 5.3b). Absolutefecundity was found to vary between 1,140 and 1,23,968(mean 20,472). The fecundity of H. brachysoma observedin the study was higher than that reported for most othercatfishes, viz. Wallago attu (Das, 1994). Clarias batrachus(Rao et al. 1994), C.macrocephalus, (Saidin,1986).Relatively high fecundity and omnivorous feeding behaviormake this indigenous catfish, a potential candidate for culture.

Investigations on artificial breeding of H. brachysoma wasundertaken for the first time, by the Regional AgriculturalResearch Station, Kumarakom as part of the NationalAgricultural Technology Project in collaboration with theNational Bureau of Fish Genetic Resources, Lucknow. It wasdemonstrated that H. brachysoma can be brought to finalmaturation and ovulation by the administration of a singledose of Ovaprim @1ml.kg-1 body weight or fish pituitary

extract @50–60 mg.kg-1 body weight, the former being moreeffective. Captive breeding was carried out successfully usingfarm reared stocks (Padmakumar et al. 2004). Theperformance of captive breeding trials and breeding protocolsare summarised in Table 3.

Historically, H. brachysoma was locally abundant in therivers of central Kerala, but populations have declineddrastically and the species is now restricted to sparsepopulations. The species is listed as endangered and iscategorized as a species of special concern by the IUCN(CAMP, 1998; Shaji et al. 2000; Gopalakrishnan andPonniah, 2000). Stocking of natural waters using hatcheryraised seeds is an important and, in some cases, verysuccessful tool for species conservation. There has beenheavy demand for the seed of this species for aquacultureand the Regional Agricultural Research Station, Kumarakomis engaged in a program for mass production of seeds of H.brachysoma for aquaculture and open stocking. Morerecently, during 2007–08, the seeds produced under thisproject was used for stocking the Sasthamcottai lake, aRamsar site in the Western Ghat region, by the StateDepartment of Fisheries. With these efforts, the Goldencatfish is on a comeback trail in the Vembanad system.

Among catfishes, males are generally not free milting.Males in most silurids are considered not amenable tostripping eg. C. batrachus, Heteropneustes fossilis (Pandianand Koteeswaran, 1998). Therefore, in Clarias, the malesare sacrificed for collecting the milt since it is not possibleto extract milt through stripping (Rao et al. 1994). H.brachysoma appears to be an exception, as mature malescould be freely stripped, like Pangasius hypophthalmus(Legendre et al. 2000) and Pangasius sutchi (Chattopadhyayet al. 2002).

Asynchrony in maturity, with males becoming mature

Table 1. Captive breeding and nesting in E. suratensis

Nesting Nest area Eggs Egg density Fertilisation Hatchingsubstrate (cm2) (No.) (no./cm2) (%) (%)

Earthen pots 56 951 17 76 90CC. substrate 32 420 13 100 63Wooden poles 18 792 44 82 20Wooden poles 37.8 1966 52 98 29Hose tube 19 382 20 100 99CC. substrate 18 633 35 95 63CC. substrate 54.4 390 7 98 90CC. substrate 27 1350 50 99 34CC. substrate 28 477 17 96 65Coconut-petiole 49.5 990 20 71 70Wooden poles 20.3 1215 60 92 13Granite block 22.5 260 12 100 48Coconut leaf 43.7 1573 36 100 10Fire brick 22.9 642 28 99 32Coconut husk 28.26 1243 44 98 38Hose tube 48.0 250 5 100 33


68

Table 2. Characteristics of pit nursing in Etroplus suratensis

Water column No. of pits Distance between Diameter of Depth of(cm) by a pair pits (cm) pits (cm) pits (cm)

18.9 10 10.43 7.24 5.022.0 13 7.5 6.21 4.023.0 11 5.82 8.5 4.324.4 15 3.91 6.0 6.025.0 9 5.42 5.79 5.025.8 9 10.33 4.33 3.6726.2 14 7.10 5.0 4.027.6 15 5.13 5.63 4.827.8 7 6.08 4.5 4.0433.2 13 5.44 5.7 3.733.8 13 6.63 4.5 3.7637.7 15 5.56 3.8 3.32

earlier than female was observed in H. brachysoma. In thecontext of the observed asynchrony in final maturation inthis species, the standardization of protocols forcryopreservation of milt of H. brachysoma (Gopalakrishnanet al. 2000) assumes significance. This also opens uppossibilities for utilization of cryopreserved milt not onlyfor germplasm conservation but also for artificialinsemination. H. brachysoma was found to abound in weedinfested slow flowing habitats, where high turbidity and lowoxygen content prevailed. It appears that catfishes have acompetitive advantage over many oxyphilic species, tosurvive in such environments. The low diversity of catfishesas pelagic communities, compared to littoral communities,is attributed to their ancient evolution of coping with hypoxicand turbid waters (Arratia et al. 2003), as rivers are old whilelakes are much more recent. This also indicates their extremeresilience to a broad range of environmental condition.

In contrast, murky waters appeared to be inimical tocichlid, E. suratensis (Cole and Ward, 1969; Samarakoon,1981). Apparently, decreased water turbidity favored visualdisplays for both feeding and breeding in E. suratensis. Visualstimuli favor and hasten ovulation in cichlids (Jalabert andZohar, 1982) and being a visual feeder pearlspot prefer clear

water for breeding. This could be an adaptation that ensuredbetter feed availability for the young ones (De Silva et al.1984). As visual contact between the parents and the offspringis a critical requirement for spawning, the increased turbidityof water in the lake by siltation and high sedimentation duringmonsoon is one of the factors that limit their naturalrecruitment, a situation that gradually changes with theinfiltration of saline water during summer.

With increasing pressure on inland fish biodiversity, arange of strategies are suggested for enhancement of naturalpopulations of endangered fish stocks. One of the strategiesfor conservation of such species is stock enhancement byartificial stocking by developing breeding techniques incontrolled conditions. Despite resolute utilization of captivebreeding in species recovery for a variety of species in recentyears, the limitations of this approach also cannot beoverlooked. It is not an alternative to habitat and ecosystemprotection and hence may be invoked most judiciously inthe absence of other comprehensive efforts to maintain orrestore populations in wild habitats. Merely demonstratingthat a population of a particular species is declining or hasfallen below what may be a minimum viable size does notconstitute enough reasons to justify captive breeding as a

Table 3. Captive Breeding protocols of Horabagrus brachysoma

Ovaprim*(N=78) CPE**(N=19)

Range Mean ±SD Range Mean±SD

Fish body weight (male)(g) 200-534 372.57±76.64 230-255 242.50±17.68Fish body weight (female) (g) 140-390 223.29±64.05 280-320 300.00±28.28Hormone dose (ml) 0.14-0.39 0.22±0.06 0.27-0.33 0.30±0.04Latency period (h) 8.0-16.0 13.19±1.83 8.0-14.0 11.00±4.24Incubation time (h) 23.0-29.0 25.36±1.74 22.0-25.0 23.50±2.12Fertilisation success (%) 80.0-100.0 97.05±5.17 50.0-98.0 74.00±33.94Hatching success (%) 23.0-100 73.09±30.56 6.0-10.0 8.00±2.83Water temperature (0C) 20.0-27.0 24.84±1.99 25.0 25.0±0.00Water pH 6.5-7.8 6.87±5.17 7.0-8.5 7.75±1.06

* Ovaprim @1 ml.kg-1 ; N - No. of trials; **Carp Pituitary Extract @ 50–60 mg.kg-1


69

recovery measure (Collares-Pereira and Cowx, 2004). Thisis principally due to unavoidable genetic and phenotypicchanges that can occur in captive breeding. Apparently thismeans that ranching of seeds is not a panacea for allendangerment and should be invoked most judiciously inthe absence of any other ways to maintain or restore naturalpopulations. Nevertheless, captive breeding operated undercarefully defined conditions of disease prevention and geneticmanagement is the crucial method for recovery of specieswhen effective alternatives are not available. All thesehighlight the dire need to develop simultaneously validprograms in biodiversity conservation through concertedpublic education, and in situ conservation efforts.

In the context that habitat management is the corner stoneof species conservation, the unique breeding behavior of thespecies was utilized for the development of a ‘fish sanctuary’for pearlspot in open waters in the Vembanad system (Fig.7).Investigations indicated that fish congregate in large numbersin this protected breeding ground and spontaneously utilizethe deposited substrates for breeding. A perceptible increasein fish abundance and catches almost six fold (120 kg c.p.u.e)was evident for scare line fishing, Vellavali (Fig.8), near thesanctuary zone during the succeeding season (Padmakumaret al. 2002). Although, the major objective of the ‘fish reserve’has been protection of a minimum spawning stock to ensurerecruitment to fished areas, the spill over effects of thesanctuary by adult fish movement from fish reserve to theadjacent waters was reflected in increased fish yield in fishingzones close to the sanctuary. With the increased availabilityof fish, the fish sanctuary zone in Kumarakom has also becomefavored resting places for water birds. A perceptible increaseof water bird counts, as high as 100 percent was reported fromthe sanctuary zone in Vembanad lake (VWBC, 2004).Apparently, these results indicate that habitat managementresulted in positive benefits for other biota, as well. Indicationsare that such fish conservation efforts through habitatrestoration can accrue wider environmental benefits than mereenhancement. Noble et al. (2004) has also demonstrated thatrehabilitation of reed beds in United Kingdom was a major

factor that enhanced the conservation of the bitterns, Botaurusstellaris, an extremely rare fish eating bird.

Rehabilitation of endangered species by habitatpreservation by establishing sanctuaries is a recognizedmethod for conservation management. Partial rehabilitationof fish species in fish sanctuaries by dropping trunks of treesetc., as convenient artificial habitats and spawning areas hasbeen reported (Thuok, 1998). Use of spawning substratesinstallations and deployment of shelter devices for fishenhancement are rarely tried in river systems. Therefore, thepresent investigations on conservation management ofindigenous fish species is a major advance towardsdevelopment of a standardized mechanism for conservationof indigenous species. The foremost challenge hauntingmankind in the new millennium is the unabated loss ofbiodiversity, caused by degradation and destruction of uniquehabitats. Restoration of aquatic habitats towards pristinecondition is an utopian view (Cowx and Gerdeaux, 2004), asour river systems have already experienced extensive land usechanges. Hence, a practical approach for rehabilitation offisheries shall be to recreate functional habitats, with focuson reinstating lateral connectivity, besides improving flowregimes and water quality.

ACKNOWLEDGEMENT

We place on record our deep sense of gratitude to Shri.K.R.Viswambharan IAS., Hon. Vice Chancellor, KeralaAgricultural University for constant support andencouragement. We are grateful to Dr S. P. Singh, and Dr.A.G Ponnaiah, National Bureau of Fish Genetic Resources,Lucknow for support and guidance. We are also deeplyindebted to Dr. D.Alexander, Director of Research, KeralaAgricultural University and Dr. Joseph Philip, AssociateDirector of Research, Regional Agricultural Research Station,Kumarakom for encouragement.

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Shaji C P, Easa P S and Gopalakrishnan A. 2000. Freshwater FishDiversity of Western Ghats. In: Ponniah A G and GopalakrishnanA, (Eds.). Endemic Fish Diversity of Western Ghats. NBFGR-NATP Publication-1, National Bureau of Fish GeneticResources, Lucknow, U.P.,India. pp. 33–55.

Thuok N. 1998. Inland fishery management and enhancement inCambodia. Inland Fishery enhancements. FAO FisheriesTechnical paper –374. FAO, Rome. pp. 79–89.

Unnithan V K, Bijay Nandan Sand C K Vava. 2001. Ecology andFisheries Investigation in Vembanad lake. Bull.No.107. CentralInland Capture Fisheries Research Institute, Barrackpore,W.Bengal. 38pp.

VWBC. 2004. Vembanad Water Bird Count, 2004. Department ofForests and Wildlife, Govt. of Kerala & Kottayam NatureSociety. B Sreekumar(Ed.). Dept of Forests and Wildlife, Govt.of Kerala. 42 pp.

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Aquatic genetic resources: Policies and regulatory mechanisms including lessonslearnt from indigenous and ancient knowledge

DILIP KUMAR, RUPAM SHARMA and GEETANJALI DESHMUKHE

Central Institute of Fisheries Education, Deemed University, Indian Council of Agricultural ResearchSeven Bungalows, Versova, Mumbai 400 061

ABSTRACT

India possesses rich biodiversity of both terrestrial and aquatic flora and fauna along with ancient and traditionalknowledge for its utilization as food, medicine, etc. The traditional knowledge along with its methods for conservationstrategies is needed to be documented and brought forward to draw suitable policies and formulate regulatory mechanismto conserve the aquatic bioresources and to reproduce them in sustainable environment friendly manner. Stakeholders’participation is the key to achieve such goals since the local communities and tribes possess the key knowledge of theregion’s bioresources and environmental phenomenon.

Key words: Conservation, Genetic resources, Policies, Traditional knowledge

Aquatic genetic resources range from microbes, planktonsto gigantic whales. There is a definite food chain present inthe aquatic ecosystem. The famous “Trophic Prism” indicatesthe intimate and intricate relationships among the primaryproducers and secondary and tertiary level consumers. At thesame time, different ecosystems are mostly inter-dependentbut self-sufficient. Various biological, biochemical andreproductive processes of complex nature support numerouslife forms across the aquatic system. The value of biodiversityis based in the functioning of these components supported bythe interactions of organisms, populations and communities.

India, is blessed with several types of ecosystems rangingfrom coldwater—Himalayan rivers and lakes; tropicalwetlands; brackish water lake—Chilka, which is largest inAsia; coastal wetlands; estuarine, coastal and oceanic systems.These various ecosystems are threatened as a result ofpollution, degradation and several developmental activitieslike over-exploitation, reclamation, etc. The ecosystemscontain a range of creatures like coral reefs, mangroves,marine algae and sea grasses, conventional fishery resources,the rare groups of faunal elements and various micro-organisms which are responsible for various interdependentfunctions.

Along with rich cultural heritage and natural resources,India harnesses tremendous traditional knowledge ofutilization of the resources and their conservation. The onlylacuna is to put these three together and make appropriateand precise policies and regulatory mechanisms for theconservation and sustainable utilization of the aquaticresources. Some of such policies have been drawn for the

terrestrial resources, the aquatic resources, however, are yetto receive proper attention.

AQUATIC ECOSYSTEM

Fresh water EcosystemThe country is endowed with vast and varied resources

possessing river ecological heritage and rich biodiversity.Freshwater fishery sites are varied like 45,000 km of rivers,1, 26,334 km of canals, 2.36 million hectares of ponds andtanks and 2.05 million hectares of reservoirs (Ayyappan andBiradar, 2004). The biodiversity assessment of freshwaterfishes is done mainly on the basis of 6 drainage systems inthe country. These are Indus river system, Upland coldwaterbodies, Gangetic river system, Bramhaputra river system,East flowing river system and West flowing river system.The Western Ghats is the richest region in India with respectto endemic freshwater fishes. Northeastern India, which hasa very high diversity among freshwater fish, does not havemany endemic species within India because of its jaggedpolitical boundary.

Brackish water and Marine EcosystemTropical marine ecosystems of Indian subcontinent

harbour a large number of species belonging to varioushabitats that include mangrove forests and swamps, estuaries,lagoons, muddy, sandy/rocky shores, and oceanic islands. InIndia, although the marine biological research has been goingon for a long time, there are several groups of living, orendangered (some extinct) organisms, about which there isno proper scientific information available. This includes

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algae, sea grass and mangrove as flora and zooplankton,echinoderm, molluscs, crustaceans and finfish as fauna.

Aquatic genetic resources of IndiaThe aquatic resources include both flora and fauna. Among

the floral species, microscopic algal forms are found to bemore than 1,500. The marine macroscopic algae; that arecommonly known as seaweeds are estimated to be about 844along the Indian coast. Only 14 species of seagrasses arefound, mainly in the Gulf of Mannar region. Mangrove

biodiversity of India, is very diversified with 65 species, mostof which are reported from Sundarban, the biggest mangroveforest (Table 1). Among the faunal groups, molluscans arethe most diversified followed by crustaceans and finfishspecies. Echinoderms and amphibians are less and most ofthe species appeared in the red data book as rare andendangered.

Corals of the Indian coast are all declared as rare andendangered species and coral ecosystem, that harboursseveral flora and fauna and one of the most productiveecosystem of marine region is known to be a fragile one.Table 2 gives an account of existing coral reefs along theIndian coast and the biodiversity. Total 71 hermatypic coralgenera represented by 200 species are reported. Mostdiversified are Andaman and Nicobar Islands followed byPalk Bay and Lakshdweep atolls.

Most of the fish species belong to the marine environmentcontributing to 64% (Table 3) followed by warm water andbrackish water species.

Need for Conservation of Aquatic Genetic ResourcesSince time immemorial, the human race is establishing

itself on the bank of water bodies, where both terrestrial andaquatic resources are available in plenty. In the world, morethan 80% of the population is settled along rivers/lakes banksor along the coast. This emphasizes the human dependencyon the aquatic resources including both living and non-livingresources. Rapid development due to urbanization and

Table 1. Biodiversity of aquatic resources

Aquatic resources Species (No)

FloraOther Algae >1500Seaweeds 844Sea grasses 14Mangrove 65Aquatic weeds ~150FaunaZooplankton >1000Crustacean 2430Mollusca 5000Echinoderms 765Finfish species 2200Amphibians ~250Avian fauna >1000

Table 2. Coral Diversity of the Indian coast

Area Type Hermatypes Ahermatypes

Gen Spp. Gen Spp.

Palk Bay and Gulf of Mannar Fringing 28 84 9 10Gulf of Kutchch Fringing Patchy 20 34 4 3Andaman and Nicobar Is. Fringing 47 100 12 35Lakshawdeep Is. Atolls 27 69 4 9Submerged Banks Patchy 5 5 – –Central West Coast Patchy 8 8 – –Indian Reefs – 51 156 21 44

Total Genera: 71, Total Species: 200 (Pillai 1971, 1977, Pillai 1983, 1986, Patel 1988, Pillai & Jasmine 1989)

Table 3. Fish biodiversity of different ecosystems

Ecosystem Fish Species (No.) Composition (%)

Cold water 154 (34 fishes are common to cold and warm water) 7.27Warm water 433 (67 fishes are common to warm and brackish water) 20.45Brackish water 171 (16 fishes are found only in brackish water, 73 are common to warm, brackish and 8.07

marine water and 82 are found in both brackish and marine water.Marine 1360 64.21Total 2118 100

Source: NBFGR Annual Report (2005)

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industrialization has resulted in the destruction of habitats,resulting in extinction of several aquatic organisms. Only afraction of these species is known to science. On the adventof the industrial revolution, the coastal regions are threatenedby industrial and pesticide pollution, habitat destruction,reclamation and rapid urbanization.

Efforts to meet growing demands for food, fiber, fuel andfresh water are ever-increasing due to population explosion.Introduction of alien species, destruction of wetlands,removal of riparian vegetation are adding to the ever-increasing threats to the aquatic resources all over the world(World Wide Fund for Nature, 2004; World ConservationUnion, 2006) with freshwater species having declined morerapidly between 1970 and 2000 than their terrestrial andmarine counterparts (Abell, 2002). In addition to this, climaticchanges are playing a great role towards the loss of aquaticbioresources. Increasingly, we see the potential value ofaquatic genetic resources for all kinds of social purposesincluding food, medicines or novel industrial applications,but they are disappearing before we have had a chance tounderstand how they might be used – and in some casesbefore we have even discovered that a species exists in thefirst place. In the late 1980s, the UN’s BrundtlandCommission issued a wake-up call by drawing attention tothe interdependence of economic, environmental andcommunity long-term well-being. ‘Sustainable development’has been a common phrase ever since.

Each step in the food chain of the aquatic ecosystem isimportant as one type of organism depends on the other.Hence, it is necessary to conserve not only the economicallyimportant species, but also the insignificant ones, as well.

Strategies for conservation of aquatic bioresourcesA coherent strategy includes an appropriate combination

of in-situ, ex-situ, in-vivo and in-vitro conservation methods.In determining the precise combination of conservationmethods to use, the following factors should be considered:

• In situ community-based, management andconservation strategy deserves priority attention wheremaintenance of the aquatic genetic resources is in thebest interest of local communities for their availablelivelihood options.

• Ex-situ or in-vivo conservation in institutional orcommunally owned water bodies to supportconservation of aquatic genetic resources that havecurrent value.

• In-vitro conservation provides a secure back-up for thedeveloping world’s aquatic genetic resources in the faceof natural and human disasters that could drive theaquatic genetic resources to extinction faster than in-situ or in-vivo approaches can respond.

Indicative priority actionsFor effective conservation of an aquatic ecosystem, it

requires prudent management of the entire catchment toachieve sustainable social, economic and ecologicalobjectives (Davies and Wishart, 2000; Gilman et al. 2004;Chan et al. 2006). This should be based on integrativeassessment and planning approaches that incorporateterrestrial and aquatic issues, including the reconciliation ofconservation and water use goals both inside and outside ofprotected areas, into a single decision-making framework(Nel et al. 2007). Systematic conservation assessment andplanning methodologies have become well-advanced forterrestrial ecosystems, but the aquatic ecosystems have oftenbeen poorly dealt with (Abell et al. 2007). In such a situation,the conservation issues should be prioritized beforeformulation of the management policies. Priority actionsshould address the following:

GeneralPriority should be given for development of policy that

promotes and support appropriate use of aquatic geneticresources and conservation. Further, development of policiesand guidelines for biosecurity, exchange, ownership, accessand benefit-sharing of aquatic genetic resources is anotherprioritized area. Benefits and costs of conservation shouldalso be evaluated and demonstrated to raise awareness ofthe issues. Establishment of funding mechanisms, legalframeworks and advocacy to support the actions ofdeveloping countries to conserve aquatic genetic resourcesshould also be given priority consideration.

ConservationConservation priorities mainly include development of

capacity for cryopreservation, including the development ofhuman and technical resources; determine the mostappropriate system for regional and internationalcryopreservation programmes as a back-up for in-situ andex-situ methods; Identify hotspots of diversity and identifythe most threatened aquatic genetic resources within thosehotspots and taking action to conserve them.

Research and informationProper cataloguing and collection of all existing

information on aquatic genetic resources in an internationallyaccessible information system along with tools for analysisand interpretation of information and for decision-making isone of the most important area which deserves priorityattention. Complete global surveys of the molecular geneticdiversity of major aquatic species are equally necessary. Theeconomies of various conservation actions and interventionsshould be critically analyzed. Improvement in thetechnologies and reduction in the cost of cryopreservationof gametes, embryos and somatic cells of most species ofaquatic genetic resources are other research priorities.

Since aquatic resources are origin of civilization, thedistribution of the same along different countries or sharing


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operate within their communities, how resources are allocatedand how conflicts are avoided or resolved. This informationcan be useful for designing development interventions ordesigning effective resource management systems

The traditional knowledge and ancient culture hasexperienced both positive and sometimes negative impacton the resources. Some of the case studies are mentionedhere to understand the lessons to be learnt:

Positive lessons of the traditionSacred Groves: In several parts of India, the temples or

shrine is located in the forest and the adjacent area belongsto the shrine. The local people preserve this as sacred groveand, thus, the biodiversity is preserved. Achara, inMaharashtra is thus preserving about 150 ha of mangroveforest that belongs to the temple. Local community does notcut the mangrove for their use, no aquaculture clearing orsettlement is allowed. Another example is Sravan Kavadiain Gujarat. Here it was believed that according to mythology,Sravan had rested his parents in the mangroves of Sindhuwhere he was killed by King Dashratha. Today some 100inland mangrove trees are being taken care of the Kachchipeople of the region (Untawale Pers. Comm).

Idol worshipping: Some wild animals of the aquatic originare worshipped and thus saved from being extinct. A placecalled Kumberjua in Goa has a festival called Mangethapni.In this festival a mud replica of crocodile is prepared andworshipped. It is considered as sacred and thus the huntingis prevented. Turtles are also considered as incarnation ofGod and thus not hunted.

Fish is incarnation: Fish is known to be a first incarnationof Lord Vishnu to save mother earth and since then it hasbeen worshipped and some are protected. There are manymarine faunal species like corals, Shankh (gastropod) usedfor prayer and considered as good omen. The areas areconserved as sacred areas.

Fishing ban: Several ban on fishing in common propertyresources such as lakes, rivers, coastal waters and creeks is acommon phenomenon observed among the traditional fishingcommunities of Eastern India and Bangladesh. During therainy season which coincides with breeding season, they stopfishing till Durga Puja. This practice is of immense value forrestoring fisheries and fish biodiversity. By law, EmperorAshoka had banned fishing during breeding season.

Negative lessons of the traditionPolluting the sacred locations: Since the ancient time,

the holy places, rivers are being used for bathing and placeofferings. This in recent times has actually been damagingthe ecosystems and the biodiversity, in turn (Jain et al. 1999).

Overexploitation: Mollusc like Conus is kept in shrinesand home that fetches reasonable value. This has lead intoover-exploitation of the shell fisheries at coastal worshippingsites like Rameshwaram, Somnath, Puri, etc. Over-tourism

of the resources has been an issue of debate. There is strongneed to unite and take a solution on the prioritization of theresource management policies.

Knowledge Gap• Lack of high quality information about the status,

characteristics, and current and future values of mostaquatic genetic resources, due to scanty knowledge andinadequately developed information systems and lowintensity of information gathering mechanism.

• A lack of inventory, analysis and design of policy andregulatory frameworks and how they affectconservation efforts.

• Lack of knowledge about how to prioritize, design andoperate conservation and utilization programs that willbe sustainable in the medium to long term.

• Limited understanding of methods suitable for valuingaquatic genetic resources and limited information onthe costs and the benefits of different conservationmethods are hampering the development ofconservation on the scale required.

Lessons Learnt from Indigenous Knowledge and PracticesLocal communities, their traditional knowledge and

practices are critically important for the commoditization ofgenetic resources. Both men and women’s key role as foodproducers link them directly to the management of geneticresources. They are in possession of unique knowledge oflocal species, ecosystems and their use acquired throughgenerations of experience. In fisheries sector or aquaticresources, the availability of quality seed to a poor farmer isout of reach most of the time. Though the farmer is aware ofbreeding practices, the constant supply of healthy germplasm,subsidy on the electricity, disease control, etc. are dfficult tomanage as majority small holder farmers are not aware.

Knowledge is generated through exposure, education andexperience. Indigenous knowledge (IK) refers to the unique,traditional, local knowledge existing within and developedaround the specific conditions of women and men indigenousto a particular geographic area. Indigenous knowledge isstored in peoples’ memories and activities and is expressedin the form of stories, songs, folklore, proverbs, dances myths,cultural values, beliefs, rituals, community laws, locallanguage and taxonomy, practices, equipment, materials,aquatic species, and their distribution and behavior.

Within the fisheries sector, many fishers have a profoundlydetailed knowledge of their environment, the species of fishthey target, and changes in the waters they fish, navigation,the seasons which influence their fishing and the techniqueswhich preserve fish. Women often have detailed knowledgeof the various systems, for instance processing andpreservation of fish under different circumstances, and ofmarkets. Fishers also have considerable knowledge aboutthe social, cultural and institutional arrangements which


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has resulted into destruction of nesting sites for marine turtles.Biodiversity get protected when the community sees a

use for it. The different livelihood strategies and interests,water tenure and organizational structures of different usergroups (by gender, age, class, ethnicity and occupation) aswell as uneven power relations in access to, use and controlover land, animal and plant resources directly influence theircapacities and incentives to conserve agro-biodiversity.

Rationale for a Need of Policy and Management forSustainable Aquatic Genetic ResourcesThe lack of effective policies is one of the constraints for

the management of aquatic genetic resources for aquacultureand capture fisheries. Although there is a contribution fromaquaculture to the world fish supply, overall managementpolicies for implementation are lacking. The continueddeterioration of a country’s aquatic eco-systems will resultin an inevitable decline in the provision of key ecosystemservices that underpin social and economic development(Postel and Richter, 2003; Dudgeon et al. 2006 and Dasgupta,2007). Due to the rapid expansion of aquaculture activities,irresponsible use of natural resources and the overexploitationof many capture fisheries have resulted in adverseenvironmental and social impacts, inter-sectoral conflicts andunsustainability. Further, non-availability of information onbiological databases of fish genetic resources and lack ofholistic approach towards management of genetic resourcesare taking a toll in the aquatic biodiversity. Territorialconflicts often drive the policymakers to shy away from theproblems. The best example is seen in the river conflicts andcommerce versus environment. The delineation andmanagement of fish stocks as fish genetic resources, on thebasis of their genetic differences is yet to be studied.Inadequate characterization and domestication of variousresources and lack of resource inventories and adequate dataon rate of over-exploitation are causing threat to the geneticresources. Hence, to stop such practices, managementguidelines and policies are required for sustainabledevelopment of fish genetic resources.

International policy framework for management of aquaticgenetic resourcesThe FAO Fisheries and Aquaculture Department produces

a report on the State of World Fisheries and Aquaculture everytwo years and occasional other publications of a similarnature, though none of these addresses yet specifically thestatus of and issues pertaining to aquatic genetic resources.FAO also publishes useful Species Fact Sheets on farmedaquatic species; however, their coverage of fish geneticresources is irregular and sometimes lacking. The FAOFishery and Aquaculture Information and Statistics Servicecompiles and publishes datasets on aquaculture and capturefisheries. The FAO Code of Conduct for ResponsibleFisheries (CCRF) together with its Technical Guidelines and

Supplements are the main instruments through which theFAO provides advice and guidance and through whichmembers are contributing to responsible aquaculture andfisheries. The Technical Guidelines cover a range of issuesincluding policy formulation and, are not limited to technicalor technological matters. The CCRF helps to catalyze andfacilitate international, as well as, regional and national,aquaculture and fisheries regulations. The CCRF is “soft law”although it does have legally a binding section, theCompliance Agreement.

The movement of live aquatic animals is a necessity fordevelopment of aquaculture on both, subsistence andcommercial level. However, such movements increases theprobability of adverse ecological impacts and introducingnew pathogens, which can have direct consequences onculture and capture fisheries that can affect the livelihoodswhich depend upon them for subsistence. To facilitateintroductions with minimal risks, it is essential to developand practice a strong, national quarantine system withstakeholder participation. The major challenges are to obtainadequate information, develop the diagnostic capacity fordiseases and assess the ecological and disease risks, toimplement disease surveillance and to implement effectivelegislations.

The CCRF emphasizes conservation of aquatic geneticdiversity and of the integrity of aquatic communities andecosystems, and responsible use of living aquatic resourcesat all levels including the genetic level. The above activitieslead towards the formulation of an international frameworkfor the management of aquatic genetic resources. Such aframework is necessary so that common strategies forimproved assessment and management can be developed.Specific strategies will be required for in-situ conservationof fish genetic resources on farms and in natural ecosystems,and for ex-situ conservation of fish genetic resources,including in-vitro gene banking of cryopreserved sperm,embryos and tissues.

Regulatory mechanisms for introduction of exotic speciesWith the rapid development of the aquaculture sector, the

demand for new candidate and diversification has increased.Several exotic species have been introduced in Indiaintentionally or unintentionally. There have been divergentviews regarding relative pros and cons of these introductions.The country is blessed with ample fish resources and theintroduction of undesirable aquatic exotic species is anemerging threat to our native/endemic fish diversity. Itadversely affects the aquaculture production systems. Thus,a scientific requirement analysis based on decision supportsystems and import risk assessment is essentially requiredfor future introductions.

In the regime of WTO, exotics and quarantine issues havetremendous significance in aqua trade. It is essential for usto be prepared for evaluating such exotic species under the


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WTO agreement. To facilitate international trade of liveaquatic animals and products, WTO has framed SPSagreement. According to this agreement, scientific evidenceof exotics causing damage to the native fauna is required forrestricting introductions of exotic species on the basis ofecological or disease risks.

Presently, all new trade agreements also underline thenecessity for responsible movement of aquatic animals. Insuch a situation, the following suggestions have been madefor preventing such unwanted introduction of exotic species-

1. The provisions of the Convention on BiologicalDiversity with respect to aquatic genetic resourcesshould be well defined

2. For creating awareness among the students issuesrelated to conservation of aquatic genetic resources inthe course curriculum in all education level should beintroduced.

3. Utilization of indigenous knowledge and belief, andinvolvement of local communities in all conservationrelated works should be there.

4. For prohibiting entry of exotic species, stringentmeasures should be carried out to prevent the possiblegene pool contamination of the native stock.

5. For the conservation and sustainable use of aquaticgenetic resources the ecosystem approach includingthe incorporation of transboundary and cross-sectoralelements should be operationalized.

6. Different institutions and agencies should be entrustednational responsibilities for conservation andsustainable use of aquatic genetic resources.

7. For transplanting Genetically Modified Organisms inthe natural water body, proper guidelines should beformed

8. All exports must be made known to the customsauthorities of the importing country in advance ofshipment.

9. Formulation of proper guidelines for the classificationand taxonomy of aquatic resources.

10. Establishment of a nodal referral centre for thetaxonomy of aquatic resources and national museumfor the aquatic resources for creating awareness forconservation.

Desired policy elementTo achieve the effective management of the aquatic

genetic resources, certain policies should be formulated toaddress the following aspects for sustainable developmentand conservation of the bioresources.

1. State and National Universities/Institutions along withNGOs to take up awareness programmes amongst thelocal communities about the values of indigenousbiodiversity and the need for its conservation andrestoration.

2. To undertake restoration or rehabilitation of degradedor modified areas of habitats of indigenous fauna.

3. Creation of proper liaison with territorial authorities,other agencies and resource users for the protection ofaquatic resources or habitats from inappropriatesubdivision, use or development and also the isolationor fragmentation of ecosystems

4. Facilitate proper linkage between Ministry ofEnvironment & Forests, Ministry of Fisheries and theMinistry of Agriculture for conservation of aquaticresources in the forests, marine reserves and otherreserves in the Region

5. To oversee impacts of any construction in waterwayson aquatic habitats, and in particular on the migrationof aquatic fauna.

6. Guide to develop and maintain a regional database andindicative map of sites to the regional database ofthreatened species

7. Heritage protection which is another way of conservingthe bioresources.

8. The policy should assure that no individual, institutionor corporation can claim ownership over species orvarieties of living organisms.

9. The policy should have proper guidelines to resolvethe issues related to the granting of patent claims overorgans, cells, genes, proteins, and other living matterwhether naturally occurring or genetically engineered.

CONCLUSION

As the earth’s population continues to grow, moreresources will be needed. Desire for material goods continuesto be a main goal for people, and these two elementscombined places an increased pressure on mother earth. It isunderstandable that an increase in population is demandingmore commodities, but with careful management of ournatural resources, a sustainable balance can be achieved.Biodiversity may be the basis of human well-being but humanhabits threaten to deplete it. The most important drivers ofbiodiversity loss are unsustainable production andconsumption, inequalities in distribution of wealth andresources, demographic developments, international conflict,and international trade and agricultural policies. These resultinland conversion, climate change, pollution, atmosphericnitrogen deposition and unsustainable harvesting of naturalresources. As ecosystems falter, threats to food and watersecurity, health care and economies grow. In such cases, careshould be taken for maintenance and enhancement of thebiodiversity in a region, including the distribution andabundance of indigenous species and ecosystems. Aconsistent approach should be there throughout the worldfor identifying the issues related to the aquatic biodiversityconservation for protecting it from the future extinction. Insuch context, there is a need of proper management policyto be formulated and implemented so that the genetic


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resources can be protected for the future use. For this purposea close network between the government, non governmentorganizations and the local communities should be there foreffective implementation of the policy and proper utilizationof the bioresources.

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Fishery biology research: glimpses on practices and application forgenetic resource conservation

M DEVARAJ

Central Marine Fisheries Research Institute (CMFRI), Kochi 682 018 India

ABSTRACT

India is bestowed with rich natural resources in which the freshwater, coastal and marine living resources are ofprime importance in view of the total dependence of the humanity on these resources for its well-being. Sustainedanthropogenic activities such as fishing, coastal industries, shipping and ports, ship breaking, dredging, agriculture andland based industries have profound impacts on these resources ranging from least serious to most serious in natureprompting appropriate regulatory and conservation measures. Voluminous research findings on the biology of theseliving organisms are extensively useful for the formulation and implementation of the regulatory measures of conservation.An estimated 650 million fish eating people out of the total population of 1,300 million require 7.2 million tons at therate of 11kg/year/head. Out of 24,618 species about 2500 occur in Indian waters in which 1570 are marine and nearly200 species are of commercial importance. Almost all the species exhibit faster growth rate and attain maturity withina year, have a high fecundity, more than one spawning in a year. South-west and north-east monsoons have a profoundinfluence on these resources. Single species dominance is noticed in pelagic resources and due to continued exploitationpelagic resource emerges as a dominant one in recent times. Most of the species studied are exposed to higher fishingpressure with symptoms and indications of over-fishing and as such the marine fisheries suffer due to inappropriateexploitation, over-dependence on trawling, target fishing, habitat degradation and resource degradation. An extensivestudy on various aspects of biology of different resource has lead to formulation of various Act and Rules on fisheryregulation on limited entry, temporal restriction, spatial restriction, gear restriction, mesh size regulation and fishingholidays. Determination of spawning season helps fixing the months of fishing ban.

Determination of fecundity and number of spawners helps finding out biomass spawning stock biomass and spawner-recruitment relationship. This, in turn, is helpful to regulate fishing effort. The estimates on growth, (based on lengthfrequency or on otoliths) is used to further estimate the mortality and stock biomass, which are necessary to understandthe status of exploitation, and further to regulate fishing effort and to fix catch quotas. Analysis of length-weightrelationship, gonadosomatic index and Kn values are useful to understand the well-being of the fish. Studies on foodand feeding habits are used to understand the tropho-dynamics and energy flow in an ecosystem, which are recentlyused for trophic modeling and for ecosystem-based fisheries management. Estimation of length-at-maturity is used tofind out whether the fish are allowed to spawn at least once in their life and to recommend Minimum Legal Size.Estimation of juveniles in the exploited populations is used to suggest optimum mesh size of fishing gear. Collection ofcontinuous data on species composition in the landings is helpful to identify the species, whose contribution decreasedonce the time period is over, and to take appropriate measures to conserve the species. Shrimp larval biology studieslead into commercial shrimp hatchery. Carp biology, induced breeding techniques, studies on shrimp biology and feedinglead into successful carp and shrimp farming and development of feeds. Studies on ornamental fish breeding biologylead into ornamental fish hatchery of the clownfish etc. Studies on fish behaviour and aggregation lead into developmentof artificial reefs & FADS. Biological characteristics studies have resulted in recommendations for conservation ofwhales, dolphins and porpoise. Biodiversity studies have helped to understand the vulnerability of coral reefs and todevelop plans for restoration of coral reefs. Biological studies on reservoir fisheries lead into stocking of fingerlings inreservoirs and harvesting fish catch. Remote sensing has helped to locate the Potential Fishing Zones (PFZ) pertainingto mostly pelagic fishery resources. Sea ranching has helped the artificial propagation of seeds of different depletedspecies in the natural environment. Artificial reefs enhance the livelihood and socio-economic condition of the coastalfisher-folk as they not only enrich the biological components of the area concerned but also congregate the fish populationleading to the improvement in the quality and quantity of the living resources of the area. Prevention of trawl operationin shallow waters will develop the area into nursery grounds for different fishery resources. Many more technologicalinterventions are Mussel culture, Edible Oyster culture, Pearl Oyster culture, Finfish culture and Seaweed culture.Further continued research in different aspects of biology, environment and climate change is essential for properconservation of the natural resources.

Key words: Biology, Capture, Culture, Fishery

April 2010] FISHERY BIOLOGY RESEARCH 79

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Decades of research on several aspects of fishery biologyhave helped to increase fish production from capture andculture fisheries, and to conserve the fish genetic resourcesto a great extent. Capture-based fishery biology research hasconcentrated mostly on maturation and spawning, growth,mortality, stock assessment and trophic-dynamics. Culture-based biological research has concentrated on natural andinduced breeding, larval development, growth and nutritionalbiology.

Practices and applicationThe following are some of the fishery biology related

research, which has high value of application forconservation:

• Determination of spawning season helps fixing themonths of fishing ban.

• Determination of fecundity, number of spawners helpsto find out spawning stock biomass and spawner-recruitment relationship. This, in turn, is helpful toregulate fishing effort.

• The estimates on growth, (based on length frequencyor on otoliths) are used to further estimate the mortalityand stock biomass, which are necessary to understandthe status of exploitation, and to regulate fishing effortand to fix catch quotas.

• Analysis of length-weight relationship, gonado-somatic index and Kn values are useful to understandthe well being of the fish.

• Studies on food and feeding habits are used tounderstand the trophic-dynamics and energy flow inan ecosystem, which are recently used for trophicmodeling and for ecosystem based fisheriesmanagement.

• Estimation of length-at-maturity is used to find outwhether the fish are allowed to spawn at-least once intheir life; and to recommend Minimum Legal Size.

• Estimation of juveniles in the exploited population isused to suggest optimum mesh size of fishing gear.

• Collection of continuous data on species compositionin the landings is helpful to identify the species whosecontribution decreased once the time period is over,and to take appropriate measures to conserve thespecies.

• Shrimp larval biology studies lead into commercialshrimp hatchery.

• Carp biology and induced breeding techniques andstudies on shrimp biology and feeding lead intosuccessful carp and shrimp farming; and developmentof feeds.

• Studies on ornamental fish breeding biology lead intoornamental fish hatchery of the clownfish.

• Studies on fish behaviour and aggregation lead intodevelopment of artificial reefs & FADS.

• Biological characteristic studies have resulted in

recommendations for conservation of whales, dolphins,and porpoise.

• Biodiversity studies have helped to understand thevulnerability of coral reefs and to develop plans forrestoration of coral reefs.

• Biological studies on reservoir fisheries lead intostocking of fingerlings in reservoirs and harvesting fishcatch.

The application value of few of the above mentionedbiological studies are outlined here.

CAPTURE FISHERY

Maturity and SpawningKnowledge of length/age at maturity, fecundity, spawning

season and spawning area has provided valuable clues forunderstanding and even predicting the changes, which thepopulation as a whole undergoes. This has led to inferenceson the rate of regeneration of stocks and further tomanagement and rational exploitation of the resources.Information on the length at first maturity has provided basisfor the rational choice of the mesh sizes to prevent overfishingof the juveniles. Identification of the season and the area ofspawning helps in the prevention of exploitation of spawners.Further, knowledge of the fecundity and the reproductivecapacity is a dynamic factor influencing the choice of theexploitation level. Information on these aspects is notavailable for a number of fish species in the Indian waters.

Length At First Maturity (Lm)Maturity is clearly linked with the growth rate of fishes

and hence, two phases in the life of fish – pre-maturity andpost-maturity should be clearly distinguished. For thedetermination of the length at first maturity (Lm), most ofthe research workers have considered only the female andassumed that the onset of maturity may not be different inthe male (Qasim, 1973). The length at which 50% of fishhad ovary in stage III and above, is normally considered asthe Lm. From the information available on several species offinfishes in the Indian waters, it could be deduced that thefishes attain first maturity at 30 to 80% of their respectiveL∞ and nearly 40% of the fish species attain first maturitywhen the length is 50 to 60% of their L∞. The species thatattain first maturity at a very late stage of their life (Lm at>70% of L∞) are the small pelagics like the oil sardine andthe Indian mackerel. On the other hand, the species whichattain first maturity at very early stage of their life (Lm <40%of L∞) are the large pelagics, viz. the ribbonfish Trichiuruslepturus, the seerfishes Scomberomorus guttatus and S.lineolatus and the dorab Chirocentrus dorab. The growthrate of fishes decreases after they attain maturity. The smallpelagics, which have fast growth rate and short longevity,delay the process of maturation and prolong the body growthprocess for a comparatively longer duration in their life thanthe large pelagics.

80 DEVARAJ [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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Spawning SeasonOne of the often-wanted information is the spawning

season of fishes. Closure of fishing when several fishes spawnin high intensity will help to conserve the spawners, andthereby, it is expected to enhance recruitment to the fishery.It is known that the tropical fishes are continuous spawners.The species that have prolonged spawning season are thosein which the ovary includes several batches of eggs, whichwill mature and spawn periodically. In these species, thepopulation consists of fishes of variable stages of maturity.In perennial spawners, almost all conceivable stages ofmaturity occur in the population throughout the year (forexample, the grenadier anchovy Coilia dussumieri Devarajet al. 1997), and hence, utmost care should be exercised todetermine the spawning season accurately. However, fordetermining the spawning season ofIndian marine fishes, the ova diameter frequency or themonthly percentage frequency distribution of stage V andabove of female are the methods considered by most researchworkers.

Most of the information on the spawning of differentspecies of marine fishes inhabiting the east and west coastsindicate that there are prolonged peak spawning seasonslasting for several months. Qasim (1973) also reached similarconclusion after reviewing the available information duringthe 1960s and the 1970s on 30 species of Indian marine fishes.There are also wide variations in the spawning season ofdifferent species. For example, some species spawn duringthe premonsoon, others during the monsoon, a few othersduring the postmonsoon, and yet others during the onset ofsummer and also during peak summer. The popular beliefthat most fishes spawn during the monsoon does not seem tohold good. The peak spawning of many species along thenorth-west and south-west coasts is during November andDecember and November to March, respectively and notduring the south-west monsoon months, i.e. June toSeptember. Similarly, the peak spawning of many speciesalong the south-east coast is during January to July and notduring north-east monsoon months, i.e. October to December.Mohanraj et al. (2002) reviewed the literature and concludedthat 41 species spawn in January and only 26 species inNovember along the south-east coast.

Spawning in fishes is initiated by a surge of gonadotropin(GtH) secretion from the pituitary gland. An important factorcontrolling the induction of GtH ovulatory surge is thegonadotropin releasing hormone which is believed to beinfluenced by the external factors like food supply,temperature, rain, photoperiod, salinity and so on. Theprolonged/continuous spawning activity among the tropicalfishes involves intricate physiological mechanisms for thesecretion of gonadotropin. It is almost impossible torecognize any particular environmental factor as thedeterminant of spawning.

In spite of the exhaustive data on the length at first maturity

and the spawning season of several species, information onmany crucial aspects related to reproduction and populationdynamics is not available. Studies on the reproductivecapacity and fecundity would yield valuable information onthe stock-recruitment relationship. However, most estimatesof fecundity provide information only on the number of eggsin the ovary at the time of observation and, at the maximum,provide a relationship between the size of the fish and thenumber of eggs. It may not be possible to apply theseobservations for solving purposeful biological problems. Toestimate the annual recruitment to the fishery, it is importantto determine the spawning frequency and the annualfecundity. The fecundity estimates have to adopt any of thefollowing methods so as to establish stock-recruitmentrelationship (Bakhayokho, 1983): (i) The number of ripe ovain the ovary (known as potential fecundity) at the pre-spawning stages multiplied by the number of spawnings givesthe total individual fecundity. (ii) The relative fecundity canbe calculated by dividing the batch and total fecundity bybody weight. (iii) The reproductive capacity of the populationcould be estimated by integrating the total individualfecundity, the size structure of the exploited stock, the sexratio, the size at first maturity and the abundance.

Feeding and GrowthThe main energy input to the animal is the food consumed.

Unlike in laboratory studies, there is no control over thequantity of food consumed by the animal in the wild, or thecomposition of diet. The food and energy intake have to beestimated indirectly.

Despite the abundance of studies on the feeding habitsand on the growth of the marine fishes, the relationshipbetween these two vital parameters has not been properlyaddressed so far for the fish populations in the Indian waters.Such a correlation is crucial for a proper understanding ofthe exploited fish populations and for modeling theecosystems, as they are relevant to the management of multi-species fisheries, where one commercially important speciesfeeds upon the other. It is vital to understand the predator-prey relationship, which determines predation mortality,which is a major component of natural mortality. Hence, aseries of attempts to develop and refine the methodologiesfor establishing a relationship is necessary.

There are several estimations on the food consumption ofaquatic populations based on the quantity of food in thestomach of the animals sampled in the wild. The weight ofthe food in the stomach provided an estimate of the foodconsumed by the fishes in the sample.

By employing this method, Devaraj (1998a,b,c) andVivekanandan (2001) reported that the estimated feedingrates of the seer fishes, and the threadfin bream and thelizardfish, respectively were within the range of valuesreported for the tropical fishes based on laboratoryexperiments.


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Regulation of mesh sizeThe purpose of controlling the mesh size, especially in

the cod end of the trawls, is to permit the escape of juvenileshoping that their growth would largely compensate the lossand increase the exploitable biomass, which might beavailable to the fishery later. Minimum mesh sizes are oftenemphasized as essential by the scientists as there is generalagreement that protection of young fish is necessary. It isoften argued that if fishing on immature fish is intense, theabundance of the species may be so reduced before itapproaches maturity that there would be insufficient adultfish surviving even if there is no fishing on them. It is alsopostulated that long term yields would increase by permittingthe faster growing immature fish to attain sexual maturitybefore exploitation, primarily because growth is most rapidin young fish. Under these assumptions, the biomass of acohort maximizes at about the age at first maturity.

The cod end mesh size (CEMS) of the trawls prevalent inIndia is uniformly very small (generally about 15 mmstretched knot to knot; but quite often, much less than this).Most fishery scientists have suggested a minimum stretchedmesh size of 30 mm. Kalawar et al. (1985) advocated acompulsory mesh regulation by legally imposing a minimumstretched CEMS of 35 mm, that would help to protectsignificant number of juvenile fishes as well as shrimps.According to Garcia and Le Reste (1981), mesh regulationwould be useful for shrimps in the long term due to thefollowing reasons: (i) since shrimps have a short life spanand rapid growth, the possible annual increase would beobtained before the completion of the first annual cycle.(ii) increasing the mesh size leads to an increase in age andindividual average weight and price/kg. The possible increasein value would be proportionately greater than the increasein tonnage.

In order to achieve an integrated management of theexploitation of demersal stocks, one should consider not onlythe shrimps but also the fishes. This becomes practicallydifficult in a multi-species fishery, where the body shapes ofdifferent species are diverse. The body shape of differentspecies is one of the important factors, which determines themesh size selection. The body shape, measured as depth ratio(finfish and crustaceans: standard length/maximum depth ofbody; cephalopods: dorsal mantle length/maximum girth ofbody) also ranges from 1.0 (Drepane punctata) to 45.0 (theeel, Thyrsoidea macrura). There is, therefore, no single meshsize, which is optimum for all the species. The suggestion ofoptimum mesh size for the trawl fishery as a whole dependson finding a balance between different species. This usuallyinvolves making a number of assumptions, among otherthings (Pauly, 1988): (i) that a given set of growth parameters(usually K and La of the VBGF) can be used to represent thegrowth of a group of species reaching similar sizes; (ii) thata given set of M values or (M/K values) can be used to expressthe natural mortality of fish of similar size occurring in the

same environment; and (iii) that the recruitments of differentspecies remain in the same ratio over a wide range of fishingmortality. Given these assumptions, optimum mesh size canbe computed for different groups using yield per recruitanalysis. These can then be used to calculate an overalloptimum mesh size.

Ecosystem-Based Fisheries ManagementAs far back as half a century ago (1955), the UN Technical

Conference on the Conservation of the Living Resources ofthe Sea recognized the importance of an ecosystem approachto fisheries management. However, the impetus to thisapproach was given only in 1995 in the FAO Code of Conductfor Responsible Fisheries. Since then, several developedcountries have begun the process of adopting the ecosystem-based fisheries management. Unlike the single speciesmodels in fisheries management, an ecosystem approach isan effective tool since it takes into account the complexityof the marine and coastal ecosystems and it is now believedthat such an approach could provide a lasting solution to theproblems of declining aquatic biodiversity and fish stockbiomass. An ecosystem-based approach to fisheriesmanagement, according to the NMFS (1999), should takeinto account the following four aspects: (i) the interaction ofa targeted fish stock with its predators, competitors and preyspecies; (ii) the effects of weather and hydrography on thefish biology and ecosystem; (iii) the interactions betweenfish and their habitats; and (iv) the effects of fishing on fishstocks and their habitats, especially how the harvesting ofone species might have an impact upon the other species inthe ecosystem. The National Research Council of the USAhas advocated one more aspect to this approach, i.e.,recognizing humans as components of the ecosystems theyinhabit and use, thereby incorporating the users of theecosystem in the approach (NRC, 1999).

An ecosystem approach could help manage fisheries in thefollowing ways (Mathew, 2001): (i) Conservation of fisheriesresources, protection of fish habitats, and allocation to fishersare the three most important considerations in fisheriesmanagement. The vantage point to start from is the fishing geargroup, because without its cooperation, it would not bepossible to adopt effective conservation measures and protectfish habitats from fishery-related stress. The ecosystemmodels estimate the carrying capacity of the ecosystems andthe biomass at each trophic level by taking into considerationthe weather and hydrography of the ecosystem and fishbiology. It also quantifies the number of craft and gearsrequired for sustainable harvest from the given ecosystem. Ithelps bring about a greater control over large-scale operationsof nonselective fishing gears. (ii) The approach can facilitatea better understanding of the tropho-dynamics in anecosystem, and also the impact of fishing gear selectivity onmarine living resources. Programs designed to conservemarine mammals and turtles may become counterproductive


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when these resources multiply in large numbers and competewith fish stocks as well as fisheries.

CULTURE FISHERIES

Stock EnhancementAugmenting the stock of fish has been the most common

management measure that is followed in the reservoirs inmost countries of the world. Ever since the reservoirs wereconsidered as a fishery resource, it had become apparent thatthe original fish stock of the parent river was insufficient tosupport a fishery.

Augmentation of the stock is also necessary to preventthe unwanted fish from utilizing the available food nichesand flourish at the cost of economically important species.However, the policies and guidelines on the subject, whereveravailable, are often erratic and even arbitrary.

Stocking of reservoirs with fingerlings of economicallyimportant fast growing species to colonize all the diverseniches of the biotope is one of the pre-requisites in reservoirfishery management. This has proved to be a useful tool fordeveloping fisheries potential of such small aquatic systems.However, stocking is not merely a simple matter of puttingappropriate number of fish into an ecosystem but needsevaluation of an array of factors, viz. the biogenic capacityof the environment, the growth rate of the desired speciesand the population density as regulated by predatory andcompetitive pressures.

Fish seed production has made rapid advances in thecountry during the last few decades either through indigenousor imported technologies. Consequently, a number ofhatcheries have come up for large-scale production of fishseed under the public and private sectors.

Hatchery TechnologiesBreakthrough in induced breeding through hypophysation

(Chaudhuri and Alikunhi, 1957) was achieved during thefifties with a thrust on mass production of quality spawn incontrolled environment, thereby reducing dependence onnatural seed collection. Scientists have successfully induce-bred different carp species like Labeo rohita, Cirrhinusmrigala, C. reba, L. bata and Puntius sarana by injectingcarp pituitary extract. This technique has been adopted widelyand forms a regular part of fish culture programme in India(Jhingran et al. 1991).

Chinese carps were also successfully bred in 1962adopting similar techniques (Alikunhi et al. 1963). Thetechnique of induced breeding of carps by hypophysationhas been followed in different species by several workers(Chaudhuri, 1960, 1963; Moitra and Sarkar, 1975; Vargheseet al. 1975; Bhowmick et al. 1986). Further, the use of varioussynthetic formulations including Ovaprim has largelyreplaced the use of pituitary and the technology has becomemore farmer-friendly. Now, Ovatide and WOVA-FH are alsobecoming popular.

Strain DevelopmentSeveral intergeneric and interspecific hybrids have been

produced in the last four decades for genetic improvement(Chaudhuri, 1959, 1973; Bhowmik et al. 1981). Monosexproduction by breeding six inverted broodstock in grass carp,common carp and silver carp has been reported for theirproduction enhancement in open water system (Naggy et al.1981, 1984). The genetic engineering practice, which isbecoming popular during recent years is gynogenesis,polyploidy and transgenics (Das et al. 1986; Das and Ponniah,1991). Sterile triploid hybrids have been produced bycrossing common carp with IMC males (Khan et al. 1988).Reddy et al. (1990) succeeded in producing triploidy andtetraploidy in rohu and catla by giving heat shocks to thefertilized eggs. Further, Reddy et al. (1998) induced triploidyin common carp. Pandian and Varadaraj (1987) producedtriploids and tetraploids in tilapia by heat shock. Varadarajand Pandian (1989 a, b) employing judicious combinationendocrine sex reversal, selective breeding and gynogenetictechniques produced super male tilapia.

Carp PolycultureThe research and development efforts during the last five

decades have greatly enhanced average fish yields in thecountry making carp culture an important economicenterprise. It has grown in geographical coverage,diversification of culture species and methods, besidesintensification of farming systems. The three Indian majorcarps, viz. catla (Catla catla), rohu (Labeo rohita) and mrigal(Cirrhinus mrigala) were the principal species cultured bythe farmers in ponds since ages and production from thesesystems remained significantly low (600 kg ha-1 year-1)till the introduction of carp polyculture technology.The introduction of exotic species like silver carp(Hypophthalmichthys molitrix), grass carp (Ctenopharyn-godon idella) and common carp (Cyprinus carpio) into thecarp polyculture system during early sixties added a newdimension to the aquaculture development of the country.With the adoption of technology of carp polyculture orcomposite carp culture, production levels of 3–5 tonnes ha-1

year-1 could be demonstrated in different regions of thecountry. Probably it is the technology of carp polyculturethat has revolutionized the freshwater aquaculture sector froma level of backyard activity to that of a fast growing and wellorganized industry and placed the country on the thresholdof blue revolution.

Brackishwater AquacultureThe importance of brackishwater aquaculture technologies

was recognized in the early seventies and All India Co-ordinated Research Project (AICRP) was initiated in 1973in West Bengal, Orissa, Andhra Pradesh, Tamil Nadu, Keralaand Goa (Rao and Ravichandran, 2001).

CMFRI initiated research at its Narakkal Prawn Hatchery


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Laboratory (NPHL) in 1976 for developing a comprehensivesystem of producing penaeid prawn seed in hatcheries.Intensive and sustained research by a team of scientistsresulted in successful evolution of an indigenous, low costhatchery technology for the Indian white prawn, Penaeusindicus (CMFRI, 1978; Muthu, 1980). Seed productiontechnology for other commercial shrimp species such as P.monodon, P .semisulcatus, P. merguiensis and P. japonicuswas also developed later (1985) by NPHL of CMFRI. TheCMFRI and CIBA had also successfully demonstrated theproven technology of selective farming of P.indicus,P.monodon and P.semisulcatus under different ecologicalenvironments. Research on broodstock development forP.monodon and protocol for developing eco-friendlysustainable shrimp farms are being conducted at CIBA,Chennai. The technology on mud crab culture and fatteningwas developed and transferred.

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Varadaraj K and Pandian T J. 1989a. First report on the productionof super male tilapia by integrating endocrine sex reversal withgynogenetic technique. Curr Sci 58: 434–41.

Varadaraj K and Pandian T J. 1989b. Introduction of allotriploidsin the hybrids of Oreochromis mossambicus female × red tilapiamale. Proc. Indian Acad. sci 98: 351–58.

Varghese T J, G P Satyanarayan Rao, Devaraj K V andChandrasekhar B. 1975. Preliminary observation on the use ofmarine catfish pituitary gland for induced spawning of the Indianmajor carps. Curr.Sci 44: 75–7.

Vivekanandan E. 2001. Production efficiency of two demersal fishspecies in the trawling grounds off Veraval. Indian J. Fish 48:123–32.

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Email: [email protected], [email protected]

Freshwater biodiversity has declined faster than eitherterrestrial or marine biodiversity over the past 30 years(Jenkins, 2003; UNESCO, 2003). According to IUCN Redlist (2007), approximately 30% of the fish species arethreatened globally most of which are freshwater. Manystrategies and priorities have been proposed to solve thiscrisis. The threats affecting the life history parameters offreshwater fish are anthropogenic, biophysical, habitatalterations, reduction of natural habitat area, construction ofdams, diversion or reclamation of river beds, introduction ofnon native species and climatic variations etc. The impact ofthese stresses lead to decline in effective population sizes,depending upon original population size and magnitude ofthe threat. Conservation efforts have been less by lack ofinformation on biodiversity, distribution, habitat require-ments, population dynamics, migration pattern and otheressential life history traits.

In the recent years, the freshwater fish biodiversity in Indiaare showing an alarming decline due to several factors andseveral species have been categorized as threatened in manyparts of the country. This emphasizes an immediate need forinitiating research and framing the strategies of actions forconservation and management techniques to protect these

aquatic life forms. The number of recognized finfish speciesin the world is estimated to be around 28,400 (updated to29,300; http://www.redlist.org/info/tables/table1.html) andof these 11,952 are found in freshwater, and another 160species require freshwater at one stage or the other, tocomplete their life cycle (Nelson 2006). According to Kottelatand Whitten (1996) East and South and Southeast Asiannations have a cumulative total freshwater finfish fauna of7447 species, with Indonesia having the largest number of1300. In India, 2,246 species of finfish have been recordedof which 756 from freshwater, 113 brakishwater and 1,368from marine environment (Lakra and Sarkar 2009). However,the natural history of the vast majority of fishes is very poorlydocumented. Of the total freshwater fishes known so far fromthe country, limited information on life history of about 125fishes are known till date, the life history traits and habitatrequirements in respect of majority of fishes are still lackingand this forms one of the major constraints in takingappropriate policies for their conservation.

Fish as a group, apart from its economic value, from abiodiversity viewpoint, has the highest species diversityamong all vertebrate taxa. Fishes have evolved a diversityof life history pattern (Breder and Rosen, 1966). Some specieshave very short life span, others may live for decades. Evenwithin a species, there may be major variations in the life


Life history traits of freshwater fish population and implications on aquaticbiodiversity conservation: a review

U K SARKAR1 and W S LAKRA

National Bureau of Fish Genetic Resources, Canal Ring Road, PO: Dilkusha, Lucknow 226 002

ABSTRACT

Knowledge on life history traits of fish and habitat requirements are very important in implementation of fisherymanagement programmes, domestication of species under captive conditions, stock identification, population dynamics,development of captive breeding technology, assessment of conservation status, utilization of fishes as biological control,in situ and ex situ conservation. Life history characteristics of fish, including maximum size, growth rate, size at maturity,fecundity and migratory behaviour, have important implications for populations as well as their risk of extinction.Though phenotypic differences in life history parameters do not provide direct evidence of genetic isolation betweenstocks, but can indicate the prolonged separation of fish and also provide a firm basis for separate management units.The variation in life history traits of fish indicate phenotypic plasticity of the species which could be an importantadoption trait, allowing them to respond to ecologically/habitat changes during their life time. Review of literatureindicates that information on the life history parameters of most of the freshwater fishes from different lotic and lenticwaters is rather fragmentary and understudied. The present paper reviews the relevance of the studies on life historytraits of fish population and their implications in biodiversity conservation, synthesis of latest developments, knowledgegaps, research priorities and highlight important issues related to conservation and management of freshwater fishes.

Key words: Biology, Conservation, Fish

86 SARKAR AND LAKRA [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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history patterns shown by different populations living atdifferent geographic locations. Life history traits reflect theways in which individuals vary their stage or age specificexpenditures of reproductive efforts in response to intrinsicand extrinsic factors that influence survival and fecundity(Swain et al. 2005). Various hypotheses have been proposedto explain diversity in life history pattern. Life history hastwo usages in fish conservation ecology and can providegeneral insights into where attention might be most profitablyfocused in monitoring and research (Adams 1980). There isalso a growing awareness about the life history traits of theecologically significant unit (ESU) of a species and the needto conserve them (MacLean and Jones 1995). Biological, aswell as, genetic characterization of wild stock of fish specieswill enable in linking ESU with evolutionary significant unit,thus the life history traits of the ESU of a species has greatneed to conserve them (MacLean and Jones, 1995) and intraspecies variation in life history traits has a strong geneticand environmental basis (Cadrin 2000, Lowe et al. 1998).

Studies on life history variation of freshwater fishescontinue to have an important role to play in fish geneticresource management and conservation, despite the adventof biochemical and molecular genetic techniques whichaccumulate neutral genetic differences between groups. Lifehistory characteristics, variations among populations andmodels of various fish species have been used forconservation and management programme of the freshwaterfishes in many countries (Tibor 2004, Pearson and Healey2003; Anna and Ramon 2002; Olson et al. 2004 andVilleneuve et al. 2005). Review of literature indicates mostof the research on life history strategies of some selectedfreshwater fishes (carps, catfishes etc.) were focused earlierfrom limited geographical range/locations (Jhingran 1952,1968, Das and Moitra 1955; David 1963; Jhingran and Khan1979; Chakraborty and Murty 1972; Chaturvedi 1976;Pathani 1980; Johal and Tandon 1983; Nautiyal 1984; Abbasand Siddiqui 1987; Tondon and Johal 1993 and Bhatt et al.1998) and very little attempt has been made so far for use ofthose information in conservation. It is also observed thatthough the biological information of Indian Major Carps hasbeen documented in the FAO synopsis series (Jhingran 1979,Jhingran and Khan 1968 and Khan and Jhingran 1975),however, detailed comparative biological characterizationand evaluation of various life history parameters (age andgrowth, size at maturity, early life stages etc.) from differentwild stocks, within a species is lacking. Most of the earlierstudies on freshwater fishes in India are either concernedwith morphology, taxonomy , pollution (Singh and Dobryal1983; Datta Munshi and Srivastava 1988; Talwar andJhingran 1991; Menon 1992 and Jayaram, 1981) or the inlandfisheries stocks or freshwater aquaculture systems (Jhingran1975). Status of knowledge on fish life history strategies,trophic ecology, the population biology, distribution patternand fish habitat requirements and their implication for

biodiversity conservation are very limited (Arunachalam2000; Srivastava et al. 2001; Arthington and Lorenzen, 2004;Arthington et al. 2004; Singh et al. 2003; Bhat 2003;Dahanukar et al. 2004; Johal and Rawal 2005; Sarkar andBain 2007 and Vinyoles and Sostoa 2007). Despite recentadvances, river based spatio-temporal information is lackingon the species distribution, habitat requirements and habitatuse pattern, migration and spawning cues, pattern ofmigration, reproductive biology, stock structure, climaticvariation and impact on fish life history etc. for most of theaquatic system. The important component of life historyparameters included are; 1) age and growth 2) age at firstreproduction and reproductive life span 3) migration and lifestages 4) reproductive season and regulating environment5) pre spawning action 6) parental care 7) early life historyand their survival 8) growth, population dynamics, survivaland natural recruitment.

Overview of life history patternsLife history characteristics of fish, including maximum

size, patter of growth, reproduction at first maturity, fecundityand migratory behaviour, have important implications forpopulations as well as their risk of extinction (Winemillerand Rose 1992). While life history theory has beenincreasingly used to assess exploitations threats to marinefish stocks arising from fishing pressure, there has been farless work on freshwater populations that face wider set ofthreats. Chonder (1999) has made a compilation of theexisting information available on the different aspects of lifehistory traits of forty-seven commercially important speciesof finfish and shellfish including 43 finfishes which include25 species from cypriniformes, nine species fromsiluriformes, two species from perciformes, three speciesfrom channiformes and one species each fromosteoglssiformes and clupeiformes. National AgriculturalTechnology Project (NATP), NBFGR, Lucknow undertookextensive studies on specific life history data of the prioritizedendangered and commercial important fishes in the two hotspot area North east and Western Ghats regions of India anddistinct populations have been reported (Sarkar et al. 2008,2009). The NATP launched in January 2000 with 6collaborators drawn from the North East and 6 from theWestern Ghats regions. Under NATP, Workshops were heldon “Germplasm Inventory, Evaluation and Gene Banking ofFreshwater Fishes” which one at CMFRI, Cochin and otherat North-Eastern Council, Shillong, Meghalaya. In both theworkshops a separate working group was formed on use oflife history trait parameters for conservation and variousissues related to biological data analysis were prioritized.The working group strongly recommended the need ofgenerating species specific life history data and requirementof habitat and ecological studies (Ponniah andGopalakrishnan 2000 and Ponniah and Sarkar 2000). Thegroup also discussed knowledge gaps and identified crucial

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parameters like fecundity, batch fecundity, annual fecundity,size at first maturity, gonadosomatic index, age and growth,length-weight relationship, oocyte size frequency profile,relative condition factor, food and feeding etc. It wassuggested that data available on life history traits in Indiamay be brought out by NBFGR, Lucknow in general formatsimilar to that of FAO synopsis.

Review of literature indicates that information on the lifehistory of the freshwater fishes from different lotic and lenticwaters is rather fragmentary, and understudied. Khan (1943)studied the development of some freshwater fishes of Punjabincluding Cirrhinus mrigala. Mookerjee et al. (1944) andMookerjee (1945, 1946) described the distinguishingcharacter of the fry of common Indian carp and the eggs offresh waterfishes of West Bengal, respectively. Ahmad (1944),Alikunhi and Rao (1951) and Alikunhi (1956) described theearly stages in the development of major carps and minorcarps. Mazumdar (1957) has prepared a key for theidentification of fertilized eggs of common freshwater fishes.Chacko and Kurian (1949) have reported in brief, about theearly life development in Catla catla. Sharma and Chandy(1961) studied on the alimentary tract and feeding habit of C.chitala. Dey et al. (1980) describes about the breedingbehavior, growth and fecundity of C. chitala. Natarajan andJhingran (1963) have made detailed studies on the biology ofC. catla from the river Yamuna. Kamal (1969) has reportedan account on the age and growth of C. mrigala from the riverYamuna. Among others, Chakraborty and Murty (1972)studied on the life history of Indian major carps C. mrigala,C. catla, and Labeo rohita with special reference to theirdistinguishing characteristics in the embryonic as well as postlarval stages. Though considerable studies has been done infishery population biology and age and growth of somefreshwater fishes by Tandon and Johal (1995) but thevalidation with other hard parts and analysis in respect todifferent wild population has not been well studied. Studieson fishery biology particularly age and growth, length weightrelationship, maturity and fecundity of IMC have been doneby various authors (Jhingran et al. 1988). Screening ofliterature shows that very limited research on major carps hasbeen done after Alikunhi and Jhingran (1975). The details ofthe life history traits of endangered Labeo dussumieri havebeen thoroughly studied by (1995b, 1997). Ramakrishniah(2000) reported some biological aspects of catfishes endemicto Peninsular India. Engeszer et al. (2007) and Mahapatra etal (2004) reported geographic range, biotic and abiotichabitats, and life cycle of the zebrafish across sites in NortheastIndia. Biswas (1991) made several attempts to study lifehistory traits of Labeo pangusia. Recently well distinctvariation of life history traits of Chitala chitala, Catla catla,Labeo rohita from various wild population have been reported(Sarkar et al. 2006; 2008a; Deepak et al. 2008 and Sarkar etal. 2009) and alternative conservation strategies are suggested(Sarkar et al. 2008b).

The life history data has been well analyzed in order tomake habitat specific relationship of different life historydata set and developing a modal value of traits using statisticalsoftwares by several countries. Notable efforts to documentor understand life-history diversity include Breder and Rosen(1966), Balon (1975, 1984), Page (1983) and Winemiller andRose (1992). Winemiller and Rose (1992) proposed that theessential features of the primary life history strategies canbe captured by the interrelationships among three basicdemographic parameters: survival, fecundity, and onset andduration of reproductive life. Breder and Rosen (1966)described reproductive modes of marine and freshwater fishgroups, reviewing virtually everything known fishreproduction to that date. The organization of Breder andRosen (1966) is by philogenetic groups, with detaildescriptions of breeding behaviour and life history traits forindividual species. Winemiller (1992), to tie life history traitsto habitat, suggested that the original r versus K dichotomyof reproductive strategies failed to capture some importantvariance in fish reproduction and suggested three basicpatterns in freshwater fish life history, including equilibrium,opportunistic and seasonal modes. Winemiller and Rose(1992) has reviewed 16 life history traits for 216 NorthAmerican fish species of 57 families by multivariate analysisand showed fundamental differences between marine andfreshwater species in modal values for numerous traits, likeclutch size, egg size, spawning season, and degree of parentalcare, but patterns for the marine and freshwater species, inseparate principal component analysis were very similar. Itis reported that reproductive diversity in fish is enormous(Breeder and Rosen 1966) with noteworthy inter specific (insome cases intraspecific) variation in most traits. Some ofthe fundamental traits relative to reproductive success of aspecies include size at first maturity, number of eggs,reproductive season length or timing and longevity (Wootton1984), as well as the number of clutches per female per year,and the variation in those traits aiming populations orindividuals or within a species. Egg production combinedwith longevity provides the familiar l and mx on which lifetable s lifetime reproductive expectation or output is basedbut this has already been measured for fish in the wild. Forlive-bearing fishes, fecundity is determined by the numberof embryos; inter brood interval, and length of breedingseason (Hubbs and Mosier 1985). Breder and Rosen (1966)summarized the reproductive modes of most fresh-water andmarine families, worldwide, with respect to secondary sexcharacteristics, mating system, breeding sites, kind of eggs,paternal care, and migration. Detenbeck et al. (1992) alsocompiled, fundamental data on life-history characteristicsfor a large number of North American freshwater fishes.Miller (1996) calculated costs and benefits of small bodysize, and its implications for life-history. Balon (1975, 1984)provided a classification of evolution of reproductive modesin fishes, detailed transitions in life stages of fishes, and


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describe general size relationships among gametes, larvalsizes, and adult body size. Wootton (1984) has analysedenormous data on size at maturity, life span, months ofspawning, fecundity, egg diameter, time to hatching,migration for 162 freshwater Canadian species, showingcorrelations of the various parameters classifying the speciesinto 10 clusters having similar traits. The strongestcorrelations were between body size and life span, body sizeand egg size, and spawning months and egg size (due toautumn spawning salmonids with large eggs). Wootton(1984) concluded that in a given geographic region, only acertain number of types of reproductive strategies arepossible, in that environmental factors, morphology, andphylogeny constrains the kinds of strategies that can evolve.Paine (1990) showed differences between darters (Percidae)with small and large body size, with the latter exhibiting thecombined traits of fast growth, maturation at large body size,larger clutches, shorter spawning seasons, and longerreproductive life spans. Winemiller (1992) hypothesized atriad of life history strategies termed periodic, opportunisticand equilibrium. According to their classification, periodicfishes delay maturation to a size sufficient for producing largeclutches, often with synchronous spawning and promotingsurvival of adults during adverse environmental conditions.Egg size is small in periodic fishes, but growth larvae andyoung-of-year are rapid. Periodic spawners also tend to bemigratory, moving to best places at the right time within arelatively predictable seasonal environment. Opportunisticstrategy fishes are typically are of small body size, with earlymaturation, frequent reproductive bouts over a long spawningseason, rapid larval growth, and high population turnoverrates, with a resulting high intrinsic rate of populationincrease, and population of these small fishes are oftenpresent at high density in spite of high adult mortality(Winemiller and Rose 1992). It is reported that there arenumerous schemes for describing and categorizing overalllife history strategies for freshwater fishes. Breeder andRosen (1966) provide the most comprehensive descriptivesummary, worldwide. Balon (1984) and others have providedvarious schemes for classification of reproductive traits,while Winemiller and Rose (1992) provide the most detailedand integrated assessment of broad life history patterns todate.

Habitat use and migrationFish habitat is defined as” habitat for fish is a place or for

migratory fishes, a set of places in which a fish, a fishpopulation or fish assemblage can find the physical andchemical features needed for life, such as suitable waterquality, migration routes, spawning grounds, feeding sites,resting sites and shelter from enemies and adverse weather”(Orth and White 1993). Most fish have complex life cyclesinvolving several morphologically distinct, free-living stagessuch as eggs, larvae, juveniles and adults. In the course of

their lives, fishes will grow by several orders of magnitudein mass and their resource and other ecological requirementsmay change drastically. As a consequence, many aquaticorganisms undergo ontogenetic shifts in habitat requirements.To meet the different requirements of different life historystages, fishes require access to a variety of habitats in thecourse of their life cycle. This requirement has twoimplications: (1) a variety of habitats must exist and (2) mustbe able to migrate between them (actively or passively).Migration requires some degree of connectivity betweenaquatic habitats, which can be highly fragmented andseparated spatially. The life history of a given species is notfixed but can vary in space or time. There is abundantevidence that life history characteristics can vary amongpopulations of a species (Heins and Baker 1987, Hubbs1996), and also that life history features like mortality curvescan vary within a population across time (Bervan and Gill1983). The study of fish habitat and migration has emergedas a key area of fisheries research in the recent years. Mostaquatic organisms require access to a variety of habitats inthe course of their cycle to meet the different requirementsof different life history stages. Embryos, larvae and juvenilesmust find appropriate shelter and feeding grounds in orderto reach the size threshold at which they maximize theirsurvivorship. Many fisheries in the rivers are based mainlyon migratory species. The high abundance attained by thesespecies may be a consequence of their tactic of migratingtowards nutrient rich habitats to spawn and using floodplainhabitats as nursery grounds.

The study of fish migrations has emerged as a key area offisheries research in the Mekong River Basin (Warren et al.1998). Balon (1975) listed the requirements for a comparativeframework useful for predicting the response of fishpopulations to different kinds of environments anddisturbances. Sarkar and Bain (2007) observed species andlife stages occupying a statistically distinct subset of the riverhabitats and were grouped to identify classes of river habitatfor conservation. Most species and life-stage groupsspecialized on specific habitat conditions revealed bymultivariate analyses of variance and a principal componentanalysis. The most numerous and diverse group wasassociated with deep depositional habitats with sandysubstrate and a third group of three species of adults andjuveniles were intermediate in habitat use. They suggestedthat river conservation for fish faunas should maintain botherosional and depositional channel habitats with depths,substrates, and current velocity. The life history variation onsize and growth in stream dwelling Atlantic Salmon havebeen reported by Letcher and Gries (2003). Recently,elemental analysis of fish otoliths has emerged as a powerfultechnique that can provide a natural tag for determiningpotential areas of endangered fish habitat, populationstructure and movement of individual fish specie. Thecomposition of fish otholiths reflects some of the habitat


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condition under which a fish was reared and otolithscomposition can record differences in ambient waterconditions specific to habitats used during a fish lifehistory(Travis and Gillanders 2005; Campana et al. 2000;Branzner et al 2004). For fishes, three demographic strategieshave been suggested to result from adaptive responses toenvironmental predictability (i.e. seasonality): periodic,opportunistic and equilibrium (Winemiller and Rose 1992).The migration related to spawning of Himalayan mahseershas been well studied by Nautiyal (2000). The distributionsof tropical freshwater fishes at the drainage basin scale canbe partly explained by the match between life historystrategies and seasonality gradients in hydrologicalconditions (Tedesco et al. 2008). Mangel et al. (2006)introduced new tools for use of life history data whenprioritizing habitats for conservation and management, withapplication to Essential Fish Habitat (EFH).

Climate variation and impacts on fish communityWhile it is broadly acknowledged that changes in the

climate have the potential to impact fish population, relativelyfew studies have addressed this issue in developed anddeveloping countries. It is well documented that globalwarming is causing the world’s waters to heat up whilerainfall patterns and sea levels are changing (WWF 2006)and therefore fishes are increasingly threatened by climaticchange (Walther et al. 2002). Reports indicate that warmwater fish sturgeon and bass, generally benefit from increasedwater temperature, whereas cold-water fish like trout andsalmon tend to suffer. Even a 2°C increase in watertemperature reduced the growth rate (Dockray et al. 1998),survival (Reid et al. 1997) and reproductive success(Vanwinkle et al. 1997) of rainbow trout. Temperatureextremes, high winds, extreme precipitation and storm eventshave all been shown to impact the growth, reproduction andmetabolism of fish species. Increase in the intensity orfrequency of such events as a result of climate change couldsubstantially increase fish mortality in some lakes. Climatechange would also result in shifts in the distribution of fishspecies. It has been recorded that the warming associatedwith a doubling of atmospheric CO2 could cause thezoogeographical boundaryfor freshwater fish species to movenorthward by 500 to 600 kilometers, assuming that fish areable to adopt successfully. Such changes in speciesdistribution would affect the sustainable harvests of fish inrivers and lakes. It is also expected that warm water fish willmigrate to regions currently occupied by cool and coldwaterfish. Climate change also effects on water levels. Lower waterlevels in the Great lakes, resulting from increased evaporationand shifts in surface-water and groundwater flow patterns,would threaten shoreline wetlands that provide vital fishhabitat and fish nursery grounds. The lower water levelswould expose new substrate, may facilitate the invasion ofexotic and/or aggressive aquatic plant species. Global

warming has also significantly reduced overall phytoplanktonnumbers as reported by Schulman (2005).

Life history and stock identificationIdentification of fish stocks is necessary to fisheries

management for allocation of catch between competingfisheries, recognition and protection of nursery and spawningarea, and for development of optimum harvest and monitoringstrategies (Smith et al. 1990; Begg et al. 1999). Differencesin the life history parameters among groups of fish have longbeen used as a basis for the identification of fish stocksbecause of the relative ease of assessing these parametersand their dual functionary as input into fisheries stockassessment and managing strategies (Begg et al. 2005). TheNBFGR has taken lead to identify the stock structure ofselected prioritized fish in the XIth plan under network modeusing morphological and molecular tools.

The main advantage in using life history andmorphological traits in studies of population structure is thatthese traits are often related to fitness to natural selection.The analysis of morphometric and meristic characters hasbeen widely used by ichthyologists to differentiate amongdifferent species and among different populations within aspecies (Tudela 1999, Murta 2000) and continue to be usedsuccessfully(Tzeng 2004, Ognjanovic et al. 2008). Studiesof morphologic variation among populations continue to havean important role to play in stock identification, despite theadvent of biochemical and molecular genetic techniqueswhich accumulate neutral genetic differences betweengroups. The morphological attributes of an organism are notautonomous, and changes in variation aspects of morphologyare coordinated (Zelditch et al. 1992). These morphologicalvariations depend upon the anatomical, functional,ecological, behavioral and evolutionary factors. Hardinget al. (1993) used seven morphometric measurements ofAmerican lobster larvae from the northwestern Atlantic oceanand identified three spatial groups, inferring three phenotypicstocks. They also found a significant effect of temperatureon the morphometric variables and extended phenotypicanalysis closer to genotype stock identification. Olsoen andVollestad (2001) reported significant differences in early lifestages (ELS) between the two populations of brown troutfrom the same stream, living either above or belowanimpassable waterfall and most of the ELS had an additivegenetic component. Wood and Bain (1995) reportedmorphological variation between microhabitat generalist andspecialist species and suggested that all species may vary inmorphology relative to their environment. Turan (2004)observed significant phenotypic plasticity of themorphometric and meristic counts among Mediterraneanhorse mackerel samples and suggested relationship betweenthe extent of phenotypic divergence and geographic distance.They also stated that significant morphological differencesdo not necessarily demonstrate restrictions of gene flow


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among populations. The meristic characters are known tovary under the influence of environmental factors especiallytemperature during early life stage (Barlow, 1961). Natrajanet al (1977) reported three-intra species population of C. catlafrom Rihand reservoir on the basis of size of the pectoralfins. Kristjansson (2005) opined that most of the freshwaterpopulation has apparently evolved after isolation of marinesticklebacks in freshwater. After colonization of freshwaterhabitats, they show rapid morphological changes andassociated genetic isolation within few generations.

Many cases demonstrate that either closely related ordistantly related fishes have substantially different life historystrategies within the same kind of habitat (Schloemer 1947,Cambray 1994) which may be due spreading out ofreproductive timing of species so that the young do not allsaturate the environment simultaneously (Kramer 1978). Lifehistory traits are influenced not only by the abioticenvironment or environmental variability but also by bioticinteractions like predation (Reznick and Miles 1989). Withina stream different levels of predator threat in which lifehistory traits of a single species can be compared in similarenvironments differing mostly in predator threat. There aresome reports that reviewed broad relationships betweengenetic structure of populations and general life history traits.Vrigenhoek et al. (1987) found different levels of geneticdivergence related to life history traits in Poeciliopsis andArctic char.

Population dynamicsDynamics of fish population seeks to provide the basic

framework for scientific advice in respect of optimization,which is the central theme of fisheries resource management.Fisheries resources are highly dynamic and mobile andfurthermore are beyond the visual horizon and many of thebehavioral aspects are still unknown. Fisheries resources arerenewable resources and therefore, a judicious managementand exploitation are of paramount need to draw sustainableyield for the years to come. The influence of hydrology onpopulation dynamics is most striking in seasonal floodplainsystems where aquatic habitat may expand and contract byover three orders of magnitude and populations may respondwith extreme cycles of production and mortality(Welcommeand Hagborg 1977; Halls and Wellcome 2003). Overallquantitative modeling of population dynamics in relation tohabitat factors, such as hydrological attributes and land usechange, is a relatively recent development (Halls andWelcomme 2003, Minte-Vera 2003). Beamesderfer et al.(2007) studied the available life history information on greensturgeon and developed a simple population model to informinterpretations of status and threats identified significantresearch needs for and supports a precautionary approach inconservation and management in the face of uncertainassessments of status and risk More studies are required, inparticular with respect to systems where large scale

hydrological modifications are likely in the future .However,climate change is likely to lead to significant hydrologicalchange within the next few decades and understandingpopulation responses to such changes will becomeincreasingly central to fisheries management andconservation.

Reproduction and recruitmentReproduction strategies, recruitment of freshwater fishes

in the natural waters are crucial for conservation andmanagement. Relative indices of recruitment (the numberof fish that have attained the age at which they are vulnerableto fishing) and abundance or biomass of early life historystages in putative fish stocks can provide information on yearclass strength and stock resilience, as well as stockrelatedness. Several authors have suggested significantregional variation in reproductive parameters (Williams 2006;Ebiswa1999; Adams et al. 2000; Platten et al. 2002).However very less data is available of these complexprocesses. Various recruitment models or hypothesis havebeen put forward, attempting to explain how fish in earlylife history stages encounter sufficient quantities of food ofthe right size, while avoiding predation. One of thepreeminent hypotheses is the match/mismatch hypothesis ofCushing (1990), which recognizes that fish spawn atapproximately the same time each year and the preyabundance is less predictable and more responsive toenvironmental conditions. Halls et al (2000) found therecruitment of a typical floodplain fish to be stronglydependent upon spawning stock biomass and biolimitingnutrient concentrations. Harris and Gehrke (1994) proposedflood recruitment model similar to the flood pulse concept(Junk et al. 1989), to explain how some species of fish in theMurray – Darling basin, Australia respond to rises in flowand flooding. Humpheries et al. (1999) proposed the lowflow recruitment hypothesis, which describes how some fishspecies spawn in the main channel and backwaters duringperiods of low flow and rising temperatures. Recently, King(2002) proposed five reproductive strategies among fishesof Australian Floodplain Rivers (generalists, floodopportunists, low flow specialists, main channel specialistsand floodplain specialists).

Growth parameters and age profileBody growth is an important population process in fish,

because it has a major impact on population biomassdevelopment as well as reproduction. Strong geographicdifferences in age or size composition, if not reflective offishing gear differences and other factors, suggestindependence of recruitment or other biological or fisheryfactors as a basis for assuming discrete stocks (Begg andWaldman 1999). Growth in river and floodplain fish isstrongly influenced by environmental conditions, includinghydrobiology (De Graf et al. 2001), food resources and


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population density (Halls 1998).Age and growth studies are important aspect of modern

fishery biological researchers as information on these areessential for interpretation of the fluctuation in the fishpopulation from location to location and to evolvemanagement practices for conservation (Johal and Tandon1983, Sheshappa, 1999). They stressed the need forundertaking studies more intensively on all important speciesof Indian fishes from all water bodies to have a distinctpopulation structure. Recent studies on age and growth offinishes using scale and other hard parts are reported byseveral authors (Kagwade 1971, Hanumantha Rao 1974,Pathani 1981, Tandon and Johal 1983, Tandon et al. 1993,Desai and Srivastava 1990, Khan 2000, Madan Mohan 2006,Licandio et al. 2006, Sarkar et al. 2006, Takaki 1960, Al-Dham and Wahab 1991, Vidalis and Tsimenidis 1996 andKerstan 2000. In India most of the studies on age and growthwere done by scale and less attempts were made so far onother hard parts and their validation with scale.

The other notable works done is Menon (1950, 1953) inwhich he has given a detail review of the studies in this lineduring the first five decades of the century; his review notonly gives a good summary of earlier work but alsoencourages workers in the tropical region of the world(specially India) to continue further studies. He believed thatinternal physiological rhythms rather than environmentalfactors were determining the formation of the growth ringbut when once their periodical regularity in appearance isproved they could be utilized for age determination. Sarojini(1958) studied the annuli in the scales of Mugil cephalusand M. percia of West Bengal and found that in each speciestheir number, identity and relative size were constantthroughout life. The annuli were formed regularly about thesame season every year and the lateral line scale were samein number throughout the life of the fish. Das and Fotedar(1965) proved that the existence of the annuli in the scale ofthe many freshwater fishes of northern India such asAnabas testudinius, Mugil cursula, Hilsa ilisha, Cirrhinusmrigala C. reba, Labeo bata, Barbus sarana and Gudusiachapra. Tondon and Johal (1983) found annual rings in thescales of Puntius sarana from river Ghaggar in Rajasthanand in Sukhna lake in Punjab, formed during March-Mayowing to spawning stress. But food and temperature alsowere suspected to have added a role in the formation of theserings. Johal and Kingra (1988) have suggested the harvestablesize of the golden mahseer Tor putitora for its conservation.Realizing the importance of age and growth, Johal et al.(1993) conducted studies on other species like Colisa fasciataand Labeo calbasu, the former from the village tank Ludhiana(Punjab) and the latter from river Ghaggar. Good annuli werefound both the species. L. calbasu population grew better inthe river than in the reservoir; juveniles of the 1+ and 0+

year-classes (i. e. the one year and 0 year olds) as well as theadvanced age phages of this species were absent in the

catches. In C. fasciata the annual weight increased directlywith age and there was growth compensation between thethird and fourth years. Johal and Dua (1994) experimentedon the effects of non-lethal doses of endosulfan and suggestedthat scales could also be used as indicator of pollution astheir surface became eroded with poisonous substances. Theyused electron microscopy in this work also. These authorscontinuing the work in the same line on Channa punctatus(Johal and Dua 1995) found the scale margins “disorganized”when exposed to endosulfan and these scales containedphosphorus, calcium, aluminium, iron, sulphur, silica andchlorine elements in them. Recently, study on age pattern ofC. chitata, Sarkar et al. (2007) reported maximum 6+ agesof C. chitala from four river basins namely river Bhagirathi,Koshi, Saryu and Ganga (Kanpur) while only 3+ age classeswere observed in the other locations (river Ganga, Rajmahal),river Gomti, river Satluj) indicating wide variation of thedistribution of population structure across geographical rangeas has been reflected in age composition which may be dueto habitat alterations or over fishing etc.

Age at first reproduction and reproductive life spanReproductive life history parameters provide fundamental

information to assist in understanding biological processesthat may be responsible for maintaining the underlying stockstructure of a species (Begg 1998). Age at maturity reflectsan evolutionary compromise between the costs and benefitsto fitness of reproducing comparatively early or late inlife(Hutchings 2002, Roff 2002).Individual stocks candevelop phenotypic and genotypic differences in theseparameters over time due to reproductive isolation (Waldmanet al. 1988), which arise from diverse environmentalconditions, differential selection pressure, and evolutionarydivergence through drift and local adaptation (Dizon et al.1992, Waldman 1999). According to Schaefer (1987)knowledge of the temporal and spatial extent of spawningcan provide information on intraspecific variation in lifehistory parameters that can be used to discriminate separatestocks. Reproductive trait has been reported to be partly undergenetic and environmental control. Many studies showintraspecific differences between populations in life historytraits, including age at first reproduction, which can be relatedto thermal effects like winter mortality (Conover 1992) or tofood availability (Jonsson and Sandlund 1979). Baltz andMoyle (1984) showed that populations of tule perchHysterocarpus traski had marked differences in age at firstreproduction, which related to longevity and size of broods.Additionally, within a population, some individual maymature earlier or at smaller size than others, often as a resultof the existence of alternative reproductive strategies or inresponse to predation pressure (Belk 1995). Stearns (1983)showed marked difference in age at first maturation inGambusia that had been introduced to various bodies of waterin Hawaii, as well as marked plasticity in age or size at


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maturation. Significant differences among population ofAtlantic salmon have been reported in size of eggs, age atmaturity and almost 500 fold increases in fecundity(Hutchings and Jones 1998). There is also considerableevidence to suggest that population variation in life historytraits reflects adaptation by fishes to local environment(Taylor 1991, Conover and Schultx 1997). Stearns andCrandall (1984) provided a mathematical and empiricalargument that plasticity in timing of maturity is adaptive,allowing fishes to optimize their fitness in differingdemographic situations. Thorpe (1994) argued that age atmaturity differences among salmonid populations suggestedmultiple solutions as evolutionary stable strategies (ESS)within species. There are reports on latitudinal differencesin life history traits in freshwater fishes. Mills (1988) showeda range in age at first reproduction from 1 to 13 years of agefor minnows Phoxinus phoxinus from south to north acrosstheir range, with concomitant trade-offs in growth and clutchsize. In a recent study Sarkar et al. (2008) reported that thesize at maturity and mean maturity percentage wasconsiderably varied in male and female Chitala chitala(afeatherback) across different river basins studied. Their studyalso showed that the male C. chitala attained maturity a yearearlier than females, which may be attributed to the fastergrowth of males than females.

Early life history traitsEarly life history is of crucial importance for the future

performance of an individual, and interest in the study ofELS of fish has increased considerably in recent years, as atool to identifying and conserving potential areas of naturalfish nurseries (Nakatani et al. 1997, Baumgartner et al. 1997).Review of literature indicates role of early life stages of fishin identifying phenotypic, genetic stocks and also ecosystemframework from various geographical locations (Hare 2005).Larval morphometrics also have been used in stockidentification similar to adult morphometrics(Harding et al.1993, Burke et al. 2000). A growing embryo or larvae facesdifferent environmental challenges and natural mortality ishigh in early life stages (Dickie et al. 1987). Paine (1984)and Paine and Balon (1986) described highly differing earlyontogenetic sequences for various darters species, and relatemicrohabitat, drifting of larvae, feeding, and overall strategiesfor survival to the differences in timing of development ofvitelline circulation or oral structures in these species. Thequantity and quality of habitat in a stream may change rapidlyrelative to the potential to allow maintenance of eggs. Inlakes, there is lower probability of disruption of spawningby flowing water, but driven waves can destroy shallow waternests. Other catastrophic destruction of eggs or larvae iscommon. Predators can cause significant mortality of eggsor larvae in nests. Temperature fluctuation can also kill larvae.Cowx (1990) showed for both roach and dace populations inEnglish rivers that growth of each species varied within a

river system, that faster growth allowed one or the otherspecies to differentially dominate the local assemblages, andthat reproductive effort was positively related with growthrate. Victor and Brothers (1982) showed that daily and annualgrowth of fallfish in different populations was strongly linkedto conditions in the local habitat, including stream size, andwas also density dependent. Winemiller and Rose (1992)pointed out a variety of fishes with divergent life historystrategies frequently co-exists in the same habitats.

Management measures relevant for conservationLife history theory can provide some general insights into

where attention might be most profitably focused inmonitoring and research (Barnthouse et al. 1990). Winemillerand Rose (1992) pointed out that a variety of fishes withdivergent life history strategies frequently coexist in the samehabitats. Diversity of life history strategies are consequentlyobserved among species that perceive the same environmentvery differently from another and as a consequences,management efforts designed to abate a problem for a givenspecies may sometimes have unanticipated effects onsympatric species that exhibit alternative strategies.Management measures aimed at conserving freshwater fishbiodiversity should be inserted into the fishery policies ofthe different State Departments. In addition, the informationgiven can be utilized by central and state governmentagencies, such as the other Development Authority, FisheriesManagement Society etc. who are deeply involved inimplementing various measures for the protection of theaquatic biodiversity. The information on population size,genetic stock and geographical distribution of threatened andendemic species should be strengthened by undertakingextensive micro geographical explorations. The knowledgeof area of distribution and information on the microgeographical characteristics of the critical habitats of theseecologically sensitive fishes will be inputs for identificationand prioritization of conservation areas /aquatic reserves forthe conservation of the species. Information regarding trophicecology, migration, breeding behaviour and breeding andspawning grounds of fishes should be generated throughextensive surveys and analysis. Such information is essentialfor both ex situ and in situ conservation of the species.Techniques should be developed for the captive breeding andbroodstock development of fishes of potential economicimportance. Commercial scale exploitation of the speciesonly be encouraged after standardizing these techniques.Such information should be extended to the small and large-scale aquarists for the enhancement of ornamental fishexports. Broodstock maintenance centres and hatcheriesshould be established exclusively for indigenous endangeredand critically endangered fishes for their in situ conservationand aqua ranching as a substitute for their natural recruitment.Investigation on the invasive nature of exotic species in thenatural habitats should be carried out with a view to establish


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how many of them could achieve natural breedingpopulations and also to what extent their feeding spectrumhabits overlap with that of the indigenous fishes. Theintroduction of exotic and alien species of fishes in openwaters for the purpose of resource augmentation should bediscouraged and before any exotic species are introduction,its potential threat to local species should be studied and theintroduction shall be subjected to the establishment of nonthreatening nature of the species.

CONCLUSION

The conservation of aquatic germplasm resources is anincreasingly important field of scientific endeavor. When anincreasingly number of species are being reported to beendangered and threatened, there needs to be a focus onmaintenance of the genetic component of biodiversity andthe preservation of evolutionary processes. The variationindicates phenotypic plasticity of the species which couldbe an important adoption trait, allowing them to respond toecological/habitat changes during their life time. Therefore,conservation needs must be aimed towards preservingexisting biodiversity and also the evolutionary processes thatfoster biodiversity The review and synthesis of the aspectslife history traits discussed above clearly indicate that theinformation on the life history traits of the fishes of all thefreshwaters is essential to carry out conservation, ecologyand aquatic resource management programme. Virtually, verylimited information in these lines are available in respect ofmajority of critically endangered and endangered freshwaterfishes and therefore, their reproductive capability,constraints, spawning season, habitat are beyond any sortof prediction. Similarly, a full advantage of the local speciesof aquaculture, ornamental or capture fisheries forconservation and sustainable utilization, the specificinformation on life history traits is imminent. The dearth ofinformation on the life history traits of many food andornamental species is the major bottleneck in theirintroduction in the international markets and taking fulladvantage in the era of IPR. Therefore, it is essential toprioritize research on above for helping the planners in takingpolicy decisions and framing of legislation, to bring outinterspecific and intraspecific variations among speciesinhabiting different localities, useful in the selection of idealbrood stocks for captive breeding programmes and also inattaining capability to undertake species-specificrehabilitation programmes. It is hoped that the results ofNBFGR’s new programme of Genetic Stock Identificationwill generate location specific data on genetic stocks of theprioritized fishes which could be useful for biodiversityconservation and management.

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E-mail: [email protected], [email protected]


Conservation biology of Indian Mahseers

W S LAKRA1, M GOSWAMI2 and U K SARKAR3

National Bureau of Fish Genetic Resources, Canal Ring Road, Dilkusha P.O. Lucknow 226 002 India

ABSTRACT

The populations of mahseers are declining very fast in different parts of India due to indiscriminate fishing of broodstock and juveniles, fast degradation of aquatic ecosystems, construction of dams, barrages and weirs under river valleyprojects etc and therefore the species deserves high conservation values in India. To save this prized resource, effectiveconservation and propagation assisted rehabilitation strategies need to be planned and implemented in the country. Thisrequires knowledge of genetic variation and population structure of mahseers in the wild habitat, which is yet notavailable comprehensively. In the present paper, an attempt has been made to review evolutionary history, present statusand need of conservation of mahseer and role of conservation biology and genetics for their germplasm conservation,sustainable utilization and enhancement. We propose new ideas and suggestions, which would help saving mightymahseers across the country.

Key words: Conservation, India, Mahseer, Neolissochilus spp., Tor

Mahseers, under the family Cyprinidae and Genus Torand Neolissochilus are described as the ‘King of Indianfreshwater systems and among mahseers, golden mahseerTor putiora and Tor tor are important as potential game as

well as food fish. Being acknowledged as an outstandinggame fish, they have been a core source of recreations forinnumerable anglers from India as well as overseas sincetime immemorial. They have been of considerable

Table 1. Conservation status of Mahseer (Tor and Neolissochilus spp)

Species Assessed for Threats CAMP, Lakra1998 and Sarkar,

2007

Tor khudree West flowing river system Dm, Fd, I, H, Ov, Po, Sn, T VU VUT. khudree East and west flowing river system Dm, Fd, E, F, I, G, L, Po, Pu, T CR NEmalabaricusT. kulkarni West flowing river system – DD NET. mosal Upland cold water bodies & east flowing F, I, Ov, Pu, T EN/N NE

river systemT. mussullah East flowing river system Dm, Fd, F, Po, Pu, Sn CR NET. progenius Brahmaputra river system I, L, T DD NET. putitora Indus, Gangetic & Brahmaputra river systems Dm, Dr, Fd, F, I, H, L, Ov, Po, EN/N EN

Sn, Lp, TT. tor Indus, Ganga & west flowing river systems Dm, Fd, F, I, L, Po, T EN/N ENNeolisschilus Teesta drainage I EN NEspinulosusN. wynaadensis West flowing river system Dm, Fd CR NE

CR- Critically endangered; EN-Endangered; VU-Vulnerable; DD- Data deficient, NE- Not evaluatedThreat

D- Disease; Dr- Drowning; Dm- Damming; E- Changes in edaphic factor; F- Fishing, Fd- Dynamite fishing, G- Genetic problem; H-Harvest; I- Human interference; L- Loss of habitat, P- Predation; Po-Poisoning; PI-Pu-Pollution; Sn- Siltation; Ov- Over-exploitation; T-Trade

importance as this group of fishes contribute much to thelivelihood as well as food security of the local fisher folk

April 2010] CONSERVATION BIOLOGY OF INDIAN MAHSEERS 99

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and the tribal people in the Himalayan ecoregion. India isconsidered as one of the richest megabiodiversity centres inthe world having two important biodiversity hotspots, theWestern Ghat and the Eastern Himalayas, which includesover 2200 finfish species. It is reported that a total of 73coldwater finfishes are available in the country, whichconstitutes 3.32% of total available species (Das and Pandey,1998). Among these coldwater fishes, mahseer (Tor andNeolissochilus species) is considered as one of the mostimportant game fish of the world and classified as highconservation value fish species freshwater systems. MacDonald (1948) narrated in his famous work “The Rod in Indiaand Circumventing the mahseer and other sporting fishes”about the sport and fighting nature of fish. In addition, it hashigh food value due to good taste and attains a very largesize up to 54 kg (Froese and Pauly, 2003).

Throughout the world, freshwater environments areexperiencing serious threats to both biodiversity andecosystem stability and many conservation strategies arebeing developed to solve the crisis. In recent years, thepopulation of mahseer is declining in different parts of Indiadue to indiscriminate fishing of brood stock and juveniles,fast degradation of aquatic ecosystems, illegal fishing,construction of dams, barrages and weirs under river valleyprojects, etc. (Nautiyal et al. 1998; Menon et al. 2000; Langeret al. 2001) and due to the above factors, several species ofmahseer are listed as endangered (CAMP 1998, Lakra andSarkar 2006) as per conservation assessments (Table 1). Thefish has high conservation significance and recently, sixIndian states have declared mahseer as a State Fish andspecial attention is being paid for their conservation (Table 2).To save this prized resource, effective conservation andpropagation assisted rehabilitation strategies need to beplanned and implemented in the country. This requiresknowledge of genetic variation and population structure inthe different wild habitat, which is yet not availablecomprehensively. In the present paper, an attempt has beenmade to review research carried out on mahseer withreference to its conservation biology and genetics for speciesenhancement, sustainable exploitation and rehabilitation.Some new ideas and suggestions for saving mighty mahseershave been suggested.

Evolutionary historyBeavan (1877) mentioned about the existing etymology

of the name, mahseer for the first time. King Someswara(1127 AD) in his ‘Matsya Vinoda’ or a chapter on angling onthe Manasollasa mentioned “Mahasila” which Hora (1951)took as a reference to identify T. mussullah. Hora (1930)described the possible evolution of the torrential sisorid fishesas induced by the rate of flow of water and the oxygen contentof water. Lacy and Cretin (1905) opined that the derivationof mahseer from Maha sher- big tiger is rather fanciful. Thenative name “mahseer”, “mahasula’ and ‘tora’ etc. probablyrefer to the large size of the scale or the head. Tilak andSharma (1982) opined that the word mahseer is derived fromthe Sanskrit word ‘Mahasalka’. Kulkarni and Ogale (1995)agreed that the name must have been derived from the word‘Mahasheel’ which is used even today by the fisher folk nearMulshi reservoir in Pune, Maharashtra for a medium- sizedT. mussullah or a large sized T. khudree. What ever be thederivation, the name commonly accepted and widely used ismahseer and is popularly applied to the species of this groupknown from the Indian sub continent (Jayaram, 2005).

Distribution and ecologyThe mahseer is distributed from Bangladesh, Nepal and

India to Pakistan and Afghanistan (Jayaram, 1999; Menonet al. 2000 and Froese and Pauly, 2003). The eastern limit ofthis mahseer is Burma. They exist in the hub and the otherrivers of Karachi coast. The fish is reported from most Trans-Himalayan countries ranging from Afghanistan to Myanmar(MacDonald, 1948 and Desai, 1994). Two species of mahseer,T. putitora and T. tor inhabit Nepalese torrential waters andlakes of mid hills (Shrestha, 1994).

In India, Mahseer is distributed all along the Himalayasincluding the freshwaters of Kashmir, Sikkim, HimachalPradesh, Uttar Pradesh, Punjab, Haryana, Darjeeling districtof West Bengal and Assam (Day 1873 and Sen and Jayaram,1982). It inhabits the mountains and sub mountains regions,running streams and rivers. The commercial fishery ofmahseer in Jammu, Himachal Pradesh and Uttar Pradeshconsists largely of individuals either ascending streams forbreeding or the spent once returning to perennial ponds inthe plains. David (1953) reported the occurrence of mahseerin the Mahanadi river near the Huma sanctuary (South India).The rivers Beas and Satluj in Himachal Pradesh like othercontemporary Himalyan rivers supports a good populationof T. putitora. Besides those of the Indus river system (Pongand Govindsagar) there are some reservoirs of the Gangariver system especially Nanaksagar and Sardosagar whichharbour Himalayan mahseer. The species is known to occurin the major river systems draining the lower Himalayanterrain, like the Indus, Ganga and Brahmaputra.

The fish shows variation in migration as reported byseveral authors. Beavan (1877) reported that T. putitorashows migration with respect to time (rain), direction

Table 2. List of Mahseer species adopted/proposedas a State Fish

Species State

Tor putitora Arunachal Pradesh

T. putitora Himachal Pradesh

T. putitora Uttarakhand

T. mahanadicus Orissa

Neolissochilus hexagonolepis Nagaland

T. putitora Jammu and Kashmir

100 LAKRA ET AL. [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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(upstream) and purpose (spawning). Khan (1939) reportedthe migration of T. putitora for spawning during August-September and returning of spent fish during October-November (Sehgal, 1978). Mahseer lives and grows tomaturity in large rivers, migrate to headwater, stream, creeksto spawn during the wet season from June to October. Manyauthors reported many views on the variations in breedingseason of the fish (Table 3). They forage in large groups overopen gravel bed and their profound habitat are snowfed orrainfed running water broken in to pools and rapids withmoderate depth of water. They are long lived, slow growing,predatory, column feeder feed on insects and fish fry of otherspecies. Nautiyal and Lal (1984) described that fish iscarnivore by habit and preferred to call it as an omnivore. Amature mahseer produces 45, 800 to 75, 000 eggs and arereported to deposit their spawn in several batches in a periodof several months (Beavan, 1877). The ecological status ofthe Himalayan mahseers has been assigned as endangered(Singh and Sharma, 1998 and Anon, 2003).

Genetic resourcesBiodiversity is defined as “variability among living

organisms from all sources including, inter alia, terrestrial,

marine and other aquatic systems and ecological complexesof which they are a part, this includes diversity within species,between species and of ecosystems” (UN Conference onEnvironment and Development). In India freshwaterresources in the form of rivers and canals (1, 73, 287 km),ponds and tanks (2.25 million ha), beels/lakes/derelictwaterbodies (1.3 million ha), reservoirs (2.09 million ha)harbour important freshwater denizen which makes them abiodiversity rich ecosystem.

The report on the available genetic resources of mahseersin India is highly ambiguous. Day (1878) believed thatmahseer constituted only one species. Later, Hora (1940)confirmed the validity of six different species. Sen andJayaram, (1982) described some uncertain species of Mahseer(Barbus hexastichus, B. dukai, B. neilli and Puntiuschelynoides). Rainboth (1985) proposed the new genusNeolissochilus to accommodate hexagonolepis. Talwar andJhingran (1991) recognized seven species of true Mahseerin India, viz. Tor putitora (Hamilton), T. mosal (Hamilton),T. progenius (McClelland), T. khudree (Sykes), T. mussulah(Sykes) and T. chelynoids (McClelland) belonging to aseparate genus. A recent critical study on the subject byMenon (1992) confirmed 6 valid species. He however,described a new species from the Darna River (Godavaridrainage) at Deolali, Nashik District of Maharashtra andnamed it Tor kulkarnii, which he described as a dwarf cognateof Tor khudree. Presently seven valid species are recognizedin India (Tabel 4). In addition to the those above, three sub-species, viz. T. mosal mahanadicus, T. khudree malabaricusand T. khudree longispinis (Desai, 2003) and othermorphotypes like Neolissochilus hexagonolepis, N.hexasticus, N. wayaanadensis (Jayaram, 1999) and N.paucisauamata, N. stracheyi (Vishwanath et al. 2007) arereported from different parts of India.

Traditional taxonomical identification of mahseers basedon morphological traits is quite ambiguous. Therefore, properidentification of the mahseers using different molecularmarkers is the need of the hour for conservation. In thiscontext, molecular identification and phylogenetic

Table 3. Breeding seasons of different species of mahseers.

Species Seasons Reference

T. putitora January–February Khan (1939), SehgalMay–June (1978) andJuly–December Karamchandani et al.

1967)T. putitora August– Joshi (1984)

SeptemberT. mosal November– Ahmad (1948a)

DecemberT. khudree July–September Kulkarni (1971)T. khudree July–September Cordington (1946)N. hexagonolepis April–October Ahmed (1948)

(peak August–September)

Table 4. Species diversity and distribution of mahseers in India

Scientific Name Common name Distribution

Tor putitora (Ham.) Golden or putitora mahseer All along HimalayasT. tor (Ham.) Turiya or tor mahseer Foothills of HimalayasT. khudree (Sykes) Deccan or khudree mahseer Peninsular IndiaT. khudree malabaricus Deccan mahseer East and West flowing riversT. mussullah (Sykes) Humpback or mussullah mahseer Southern IndiaT. kulkarnii Dwarf mahseer Southern IndiaT. progeneius (McClelland) Jungha of the Assamese North East IndiaT. mosal (Sykes) Copper or mosal mahseer North East India, Manipur, Arunachal PradeshNeolisschilus. hexagonolepis Chocolate mahseer North East HimalayasN. spinulosus Mahseer Teesta river (Sikkim)N. wynaadensis Mahseer Westernghat (Kerala) and head waters of Cauvery river


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relationship have been initiated at National Bureau of FishGenetic Resources (NBFGR), Lucknow among mahseers(Mohindra et al. 2006).

Biodiversity lossIrrational fishing practices, environmental aberrations in

the form of reduction in water volume, increasedsedimentation water abstraction and pollution over the yearsmake freshwater fish biodiversity a declining trend. Theincreasing trend of human population coupled with other bioticand abiotic factors is the root cause for the loss of biodiversity.Often it is difficult to discuss the causative factors thatinfluence loss of species. Moyle and Leidy (1992) listed fivebroad categories as responsible for reduced biodiversity ofaquatic organisms, these being competition for water, habitatalteration, pollution, species introduction and commercialexploitation. Kottelat and Whitten (1996) considered thebiological changes that environmental degradation bringsabout and enumerated pollution, increased sedimentation, flowalteration and water diversion as the main causes. The numberof threatened species is likely to rapidly increase in regionswhere human population growth rates are high. Singh et al.(1995) reported a sizeable reduction of mahseer catch fromBhimtal lake, Kumaon Himalayas (Table 5).

Habitat destruction and associated degradation andfragmentation are the greatest threats not only to terrestrialspecies but also to aquatic species. Habitat degradationcaused by soil erosion, siltation and turbidity due todeforestation in the catchment areas results in the alterationof ecological conditions. The changes in the ecologicalcondition become uncongenial for survival of the endemicfish. Soil erosion also leads to the destruction of breedingand spawning as well as nursery grounds of mahseer.Irrational collection of boulders and gravels from the riverbedfurther deteriorates breeding ground by removing requiredmaterials of mahseer eggs for hatching.

Construction of dam and barrages put obstruction inmigration of fish and thereby hampering breeding of mahseer.

The Tehri Dam Project in Garhwal Himalaya has an impacton production of mahseer (Figure 1). Excessive trapping ofwater through canals and channels for irrigation and drinkingpurposes deplete carrying capacity of river and finally depletsichthyofaunal diversity (Dhanze and Dhanze, 1994).Indiscriminate killing of broodfish and juveniles bydynamiting and poisoning cause drastic decline in thepopulation of mahseer. Large sized mahseers are the mostconvenient targets of the poachers being killed withexplosives. Massive collection of fry and fingerlings ofmahseer by local fisherman during downward migration isalso one of the important reasons for fish populationdeclination. Unless the consumer will be conscious aboutthe gravity of the problem of species declination this illegalmarketing of the endangered fish can’t be stopped.

Pollution of rivers and lakes by domestic wastes, sewageand industries effluents results in the deterioration of waterquality which in turn declines mahseer. It also affectsreproduction capability of fish. The obvious outcome ofpollution is stress and mass mortality of individuals. In casesof genotoxic pollutants, the effect can be more damagingbut subtle. A number of fishes have been displaced oreliminated from their original habitats.

Inbreeding depression is the most serious problems ofendangered fishes with small population sizes (Jensen, 1994).Stunted body growth and skeletal as well as body deformitieshave been noticed among a few specimens of the endangeredmahseer (Tor putitora). Recent studies have demonstratedthat introduction of certain exotic species in the reservoirshave greatly affected the mahseer fishery. Introduction ofexotic species as a part of aquaculture for commercial gainshas resulted in loss of diversity. For e.g. the Schizothoracinefishes in Kashmir valley have almost been exterminated bythe exotic common carp Cyprinus carpio species. The Loktakfish of Manipur is fast disappearing, once again, due to theintroduction of common carp for culture. The displacementof Catla species from many reservoirs and its associated

Table 5. Trend of mahseer (Tor spp.)catch from Bhimtal lake,Uttarakhand, India

Year Total catch Catch of % of mahseer in(kg) mahseer (kg) total catch

1979-80 850 707.00 83.171980-81 930.00 776.00 83.441981-82 835.00 562.00 67.301982-83 1230.00 892.00 72.521983-84 1300.00 635.00 48.851984-85 1310.00 503.00 38.401985-86 1090.00 603.00 55.831986-87 960.00 433.00 45.101987-88 960.00 – –1988-89 1210.00 635.00 52.481989-90 830.00 416.00 50.12

Fig 1. Impact of Tehri Dam Project in upper Ganga on annualproductivity of Mahseer (Tor spp.)


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ecological disaster is noticed after introduction of silver carpas in Govindsagar and some other reservoirs. In Govindsagarreservoir T. putitora (from 63% to 3%) is almost replaced bythe accidental introduction of silver carp and common carp(Sinha, 1994).

ConservationGlobally threatened species frequently require a

combination of conservation responses to ensure theircontinued survival. These responses encompass research,species-specific actions, site and habitat based actions, policyresponses and communication and education. Majority ofthe threatened species require substantially greater action toimprove their status. While many species already receivesome conservation attention, many others do not. Speciescan be saved and many already have been saved fromextinction (IUCN/WCU). However, this requires acombination of sound research, careful co-ordination ofefforts and, in some cases, intensive management. Improvingthe effectiveness of conservation action requires a betterunderstanding of the needs for such action across species,the extent to which it is being applied and the effects it hashad in preventing species extinctions. In view of the steadyreduction of mahseer in numbers and sizes in different partsof the country, it is therefore imperative that propermanagement, conservation and propagation of theseresources is ensured to protect them from further depletion.Some conservation strategies have been discussed andrecommendations suggested.

Restoration of habitatSeveral measures have been enumerated for their

conservation (Kulkarni and Ogale, 1995 and Ogale, 1997).The artificial propagation and distribution of resultant fryand fingerlings into different waters constitutes are some ofthe most important steps to rehabilitate the species, as is beingdone for the well known salmon in American and Europeanwaters. However, for dependable and continued results,improved aquaculture practices for the breeding of mahseerunder controlled conditions play a vital role. As a fewconservation and rehabilitation programmes for mahseerhave already been initiated, it appears that the fish is notendangered in lakes and reservoirs but it is endangered insome natural environments (rivers and streams).

Suitable stretches of the rivers should be considered forranching of mahseer fingerlings. Ranching is defined as anaquaculture enhancement system in which juveniles arereleased to grow unprotected on natural foods in waters fromwhich they are harvested at marketable size. Ranching isnothing but means of taking advantage of the naturalenvironment to grow fish in open waters. Ranching could bea timely and promising measure for rehabilitation of theendangered mahseer. The lack of a well established hatcheryfacilities for mahseer and for rearing of its seed was one of

the major obstacles in introducing the mahseer ranching.Mahseer have a short return migration and will burn less fatwhile traveling back to their parent rivers. This makes it avery promising candidate species for ranching. The solepurpose of mahseer ranching would be the rehabilitation ofthis fish in all rivers, lakes and reservoirs where they were inabundance or could be established. Kulkarni and Ogle (1978)developed hatchery technology of T. khudree andexperimented on successful propagation in Maharashtra,India. Further methods of transporting mahseer eggs in moistcotton (Kulkarni and Ogale, 1979) to different parts of thecountry facilitate mahseer ranching programme to besuccessful one.

Wild mahseer fry usually descend the streams in the winterand hatchery reared fry are released at the same time tosynchronize their out migration with that of wild frypopulations. Shreshtha (1994), developed a dynamic planfor river ranching. Hatchlings should be grown to thefingerling size and then released into reservoirs anddownstream rivers. Habitat fingerprinting through elementalanalysis of otolith is also an innovative approach to identifythe potential breeding in spawning grounds of mahseers inthe rivers/streams.

A method of artificial imprinting coupled with ranchingis also suggested for conservation of the species. Imprintingis an irreversible learning process in which at a criticalimpressional age of its life span an animal gets a life-longimprint of any chemical or sound to which it is introducedand this has a bearing on its future behavior. Imprinting couldbe sound or chemicals. The large aquatic environment inwhich ranched fish stock may migrate to feed or for otherreasons will make it potentially important to train and recallthem by some means. It has been demonstrated that it is thesense of smell by which some fish recognize the waters inwhich they hatched and from where they migrate to the sea.This phenomenon has been termed ‘imprinting’ and such fishare called anadromous fish, such as salmon and hilsa. It hasbeen observed at Tata Power Company Ltd., Lonavala(TPCL) fish farm it is possible to train the mahseer tocongregate near a sound source in the ponds, lakes andreservoirs.

Ex situ conservationEx-situ conservation involves the collection, handling and

management of germplasm and its storage, regeneration,characterization/evaluation, documentation and dissemi-nation to users. Ex situ conservation may involve preservationof the gene pool as an insurance against loss in situ reserves.The ultimate ex situ measures are the gene banks wherecryostorage of gametes and embryos are achieved. Thetechnique of cryopreservation of mahseer milt has beensuccessfully developed and gene banking of endangeredmahseer is technically feasible. NBFGR, Lucknow, India hasstandardized the long-term cryopreservation of milt of


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T. putitora and T. khudree at an experimental scale. Patil andLakra (2005) standardized a protocol for cryopreservationof spermatozoa of the endangered mahseer, T. khudree(Sykes) and T. putitora (Hamilton). Efforts on the inductionof triploidy and gynogenesis in mahseer using heat shocktreatment for manipulation of sex ratio are in progress.Basavaraja and Hegde (2004) and Basavaraja et al. (2006)cryopreserved the spermatozoa of the Deccan mahseer(T. khudree) using different strategies and evaluated viabilityof the cryopreserved spermatozoa. Immotile spermatozoapooled from 2 to 4 males were diluted with modified fishRinger’s solution (pH 7.48) and protected with dimethylsulfoxide (Me2SO) at 5–15%. The fish produced fromcryopreserved spermatozoa were as normal as normallyproduced fish.

In situ conservationThe concept mainly revolves the conservation of endemic

and endangered species. This method has the advantage ofbeing less expensive than ex situ measures in the long runand also allows continued co-evolution with other species inthe natural system. Menon et al. (2000) suggested thatsuitable segments of the rivers with mahseer should beidentified for establishment of ‘fish sanctuaries’. Along thestrophes of different rivers in India, there exist someimportant pockets of water-ways where the fish are preservedout of religious issues because of location of the holy places,shrives, temples on the bank of the rivers. At present fishingis prohibited on religious grounds in certain stretches ofGanga, eg. at Har-ki-paudi, Haridwar and also in some templeponds besides areas of wild life protected area. Many Hindutraditions in India are related to the conservation of plantsand animals by associating them with one or other deities.Jayaram (2005) mentioned about some protected areas byside of temples as in Dehu, Alandi on river Indrayani, Sringerion Tungabhadra, Ramanathapura on Cauvery and certainwater bodies of the sacred groves where mahseer is guarded.However, the fish sanctuary concept of freshwater fishes isyet to get policy and research support in India. Recent studiesreported that fish protected areas can play significant role inmaintaining or enhancing recruitment in unprotected areas,even many species which have become endangered in otherplaces should stable population in the protected waters(Sarkar et al. 2005, 2008).

One of the prerequisites for undertaking conservation andmanagement of fish germplasm is good mapping of waterresources which can be addressed by remote sensing andgeographic information system (GIS). Srivastava et al. (2001)studied habitat utilization pattern of T. putitora using satelliteimage in GIS and successfully identified optimum anddegraded habitat areas of river Ladhiya in Kuman Himalayas.Sarkar and Bain (2007) developed a set of habitat classes ofdifferent life stages of Tor species of river Ganga and founddefined habitat using multivariate and principal component

analysis. The experiences of Tata Power Company Ltd.,Lunaval in collaboration with NBFGR, Lucknow could beutilized in setting up a live gene bank in the region.

Indiscriminate fishing should be stopped particularlyduring June-July to end of September to prevent killing ofbrood fish. Protective legislation on mesh size, closed season,declaration of sanctuaries, limit on catches, restriction ofeffort, prohibition of use of destructive method of fishingare required. Menon et al. (2000) reported that since thereare no restrictions on the use of gill nets of smaller meshsize and fishing activity is carried out through out the year,juveniles and brood fish are invariably killed. Unscientificand spurious fishing methods like explosives andichthyotoxic plants, which not only kill the desired fish butalso pollute the water bodies are also affecting mahseerpopulation adversely.

Various conservation measures require mass awarenessand sensitization among various stakeholders about theproblem its methods and consequent people’s participationcan only probably bring out a desirable change. Preventionof environmental deterioration can be achieved through massawareness programme and with active participation of thelocal population. Several workshops have been organized inthe past to focus attention on the need for urgent steps to beundertaken to conserve this important game fish in India andAsia. The experience gained has shared with eminentscientists and other stakeholders from different states. Suchactivities indicate growing awareness towards protecting andconserving mahseer.

Angling as a hobby should be promoted and the revenuegenerated through the sport fishing would be a lasting wayof strengthening conservation. Angling festival promotespublic awareness on endangered mahseer so that destructivefishing methods and catching brooders during breedingseason can be prevented. A few Anglers Associationsincluding Assam Anglers Association (Bhoreilli), Tezpur, AllIndia Anglers Association, New Delhi, the Environment andAnglers Club, Dehradun, Wildlife Association on the Cauveryetc. are also involved in the effort of mahseer conservation.

A series of mass awareness programmes were organizedby NBFGR, Lucknow in the Kumaun region and NorthEastern Himalayas. “Mahseer Bachao Gosthis” werelaunched at local scale to sensitize local people. Socio-economic aspects of conservation and the role of anglers havebeen evaluated in selected areas exploring the possibility ofcommunity participation. Since the pattern and regulationof fishing have a great impact on the fish population dynamicsin the streams, detailed information on fishing methods underoperation in Kumaun region were documented (Srivastavaet al. 2002). This includes eight indigenous methods beingused by the local community.

Artificial propagationThe consumption of fishes suffers from the fact that the


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finfish conservation comes under the perview of more thana single governmental agency, such as those responsible formanagement of fisheries, forestry, wildlife, irrigation etc. Theartificial fertilization of eggs of the mahseer (T. khudree)was successfully carried out on a large scale for the firsttime by Kulkarni (1971) at the Tata Power Company’s fishfarm at Lonavala, District Pune (Maharashtra). Since thenconsiderable knowledge has been gained and practicalknowledge has been achieved in recent years on the spawningseason and habits, methods of artificial propagation, hatcherymanagement, rearing of fry, fingerlings and broodstock andmost importantly, on the success of hypophysation (inducedbreeding) of pond-raised stocks of all the major species, i.e.T. khudree, T. mussullah, T. tor and T. putitora (Kulkarniand Ogale, 1986 and Ogale, 1997).

At Lonavala, T. putitora, like other species, is observedto spawn naturally in lakes from July to September. Torputitora females have responded to stripping, withhypophysation (Kulkarni and Ogale, 1986). It would beworthwhile to try and breed T. putitora in the other twomonths, i.e. January and December, during which breedinghas not been attempted due to shortage of brooders. Breedingseason of all mahseer species extends from July to Septemberwith a peak in July–August and in exceptional cases toOctober, and even beyond. This has shown the adaptabilityof the species to different environments.

Attempts to breed T. putitora by hypophysation were firstmade by Sehgal and Kumar, (1977) at Baintwali mandi,Dehradun with little success. Artificial fecundation of Torputitora has been reported by Tripathi (1977) and Joshi(1984) from the Kumaon hills of Uttar Pradesh. Ripespawners were collected during the peak breeding season(July-September) and stripping was done. The spwanersranging from 365–450 mm in total length and 365–800 gmin weight yielded 4, 200 eggs/kg of body weight. The averagefecundity of putitora mahseer ranged between 26, 998 to 98,583 in the weight range of 3.5 to 23 kg (Nautiyal and Lal,1985).

Female golden mahseer of 3–5 years old spawned withouthormonal use when reared in ponds at the rate of 1 000 kg/ha with 30–40 percent crude protein supplementary feed.The majority of the fish attain sexual maturity in 70–77 cmsize range, while 1/3rd of them may attain maturity for thefirst time soon after attaining length of 40 cm. Ogale (1997)opined that breeding of golden mahseer using ovaprim wassuccessful. Studies on maturity and fecundity of T. putitorahas shown that the fish carries multimodel ova and the eggsmaturing in batches (Khan, 1939). The mahseer hatcherytechnology developed by Tata Power Company Ltd. Lonavala(TPCL), India, may well lead to the revival of mahseerfisheries in Indian waters, provided standardised simplemahseer hatcheries based on TPCL technologies could beset up in the rural areas adjacent to rivers and reservoirs(Ogale, 2006).

Aquaculture potentialFor further promotion of mahseer aquaculture one

alternative could be the development of suitable breedingand rearing technology, which requires knowledge of theirnutritional requirement from hatchlings to adult stage. Atpresent, there is only limited knowledge on feed, feedingand nutritional requirement of mahseer. Based on the growthperformance, conversion and feed utilisation a 40% proteincontent in the feed is optimal (Keshavnath, 1986). Thecompatibility of mahseer with other major carps undercomposite fish culture was tested at different densities andfeeding the fish on a fish meal based diet. Mahseer growthwas higher under composite culture than that of monoculture.

Aquaculture of mahseer, T. putitora commenced inseventies with the success on the breeding of wild stocks atBhimtal in Uttar Pradesh (Tripathi, 1977 and Pathani & Das,1979). Subsequently the efforts made by Joshi and Malkani(1986) elaborated the techniques of artificial propagation ofmahseer, T. putitora with the successful rearing. Mahseerswere considered as carnivorous and slow growing and thusunsuitable for fish culture. However, a careful study of thefeeding habits of mahseer indicating that it is omnivoroushas dispelled the notion that mahseer are carnivorous. Studieson the anatomical adaptations of the alimentary canal systemalso confirm that mahseer are omnivorous. Tripathi (1995)suggested the inclusion of mahseer in polyculture, cageculture and river ranching.

The golden mahseer fry produced at Bhimtal, India havebeen raised in subtropical pond environment to raise largefingerlings up to 210 m in length and 150 gm in weight byfeeding the fish with specially developed balanced feed thusestablishing the possibility for its culture in ponds (Vass,2000). Recent trials with the monoculture of T. putitora inponds at Lonavala were encouraging. The mahseerfingerlings were given only pelletized feed made of rice bran,groundnut cake and fishmeal (30:30:40), with a mineral mix.The average growth reported was 110 g and 90 g at stockingdensities of 10 000 and 20 000/ha, respectively, at the end ofeight months. Water temperature during the growth periodwas between 24°C and 28°C. The results of these studiesindicate the suitability of mahseer not only for inclusion incomposite fish culture but also for monoculture. Sincemahseer accepts pelleted feed and is capable of utilizing itefficiently, the species can also be used for river ranchingand cage culture. Studies carried out at the TPCL fish farmalso confirm that mahseer grown on pelletized feed developsinto excellent broodstock for induced breeding.

For the first time culturing of golden mahseer and Deccanmahseer in floating net cages has been tried at Walwhan Lake(Ogale, 2006). The size of the net cage is 9 m2 (3m x 3m),with a depth of 3 m. The net cages are fixed in the lake overmore than 4 meter depth. Fingerlings, each of 35 to 40 g,were stocked in January 2001 at a rate of 450 per cage. Thestocking density is approximately half a million/hectare. The


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fish are being fed twice a day for 10 to 15 minutes withpelletized feed. The mahseer has grown to an average of 170g in 5 months. Recent observations predict excellent resultsand would promote cage culture in India. These cage cultureexperiments are being coupled with ranching and imprintingwith sound. In earlier experiments the imprinted fish releasedin the ranching area of Walwhan Lake responds to the soundimpulse to which they were trained while in cages and cometo the shore (Ogale, 2006). Cage culture experiment ofmahseer has been conducted. After 150 days of culture theaverage net weight of T. khudree increased from 35.2 g to106g and the average net weight of T. putitora from 14.6 g to52.4 g .

Genetics and biotechnologySince increasing number of species are reported to be

endangered and threatened these needs to a focus onmaintenance of the genetic component of biodiversity andthe preservation of evolutionary process (Moritz, 2002).Devising methods of managing threatened species in orderto maintain genetic variability requires the identification ofevolutionary divergent population estimation of geneticvariability within and between population and the assessmentof conservation value of the population. Molecular geneticdata are also useful particularly valuable in confirmingtranslocation events and for assessing the genetic interaction.Therefore, to save this important mahseer genetic resource,effective conservation and propagation-assisted rehabilitationstrategies are necessary. However, this may not be feasibleunless data is available for on stock structure and geneticvariation of mahseer throughout its distribution range.Identification of polymorphic markers with consistentscorable alleles is a crucial step to generate populationgenetics data (Ferguson et al. 1995).

The conventional morphological and osteologicalcharacters based on head length and body has been used foridentification of various species of mahseer. There has beenconsiderable plasticity in the morphological characteristicsthat lead to taxonomic ambiguities, which highlight the urgentneed to resolve taxonomic conflicts in the Tor group usingmolecular markers irrespective of life history stage. Inaddition to solving taxonomic ambiguities, geneticrelatedness between different species can also be studied andRandomly Amplified Polymorphic DNA markers for Torspecies have been identified (Anon, 2003).

Polymorphic microsatellite markers identified throughcross-species amplification of microsatellite primers fromrelated species were used for differentiation of mahseer stocksfrom natural population across its natural distribution. Sevenpolymorphic microsatellite DNA loci were identified ingolden mahseer, T. putitora, through cross-speciesamplification the. The results indicate that the identifiedmicrosatellite loci exhibit promise for use in fine scalepopulation structure analyses of T. putitora (Mohindra et al.

2004). These will also provide potential tool, for assessingthe genetic bottlenecks, occurring in natural populations ofT. putitora.

Genetic population structure analysis of natural populationof T. putitora has been carried out using the identifiedpolymorphic microsatellite and allozyme markers from riversof Indus, Ganges and Mahanadi river system (Ranjana, 2005).The study revealed moderate level of population sub-structuring in T. putitora. Allozyme markers were alsodetected based on screening of 16 enzyme systems whichyilded 27 scorable loci (Anon, 2003). This information canbe used to identify the population from a single homogenousrandom mapping population or not.

Cytogenetic characterization of mahseer has providedgenetic information to resolve some of the taxonomicambiguities among the Tor spp. All the four Tor species (T.putitora, T. tor, T. khudree and T. mussulah) exhibited diploidchromosome number (2n) is 100 (Khuda-Buksh, 1980, Lakra,1996 and Nagpure, 2002). The development of silver neitherstaining technique to detect metaphase chromosome sites ofNOR (Nucleolar Organizer Region) has significantlyfacilitated comparative studies of NOR variation within andbetween species of mahseer. NORs are present on four pairsof chromosomes in T. putitora and T. tor (Nagpure et al.2002) whereas Barat and Ponniah (1998) reported NORs ontwo pairs of Chromosomes. Variations in karymorphologyand NOR banding pattern can be used as cytogeneticintrogression among these closely related species. NORbanding pattern has also been used to study intraspeciespolymorphism in T. putitora (Barat and Ponniah, 1998).

Short term and continuous cell cultures from a varietyfish species have been reported in the past and appliedextensively in virological, toxicological and cytogeneticstudies (Chen et al. 1986 and Hightower and Renfro, 1988).Hence establishment of cell lines from economicallyimportant and endangered species would be of greatimportance for aquaculture and fisheries management. Lakraet al. (2006) developed a diploid cell line (TP-1) for the firsttime from the golden mahseer (T. putitora) which haspotential application in biodiversity conservation of thespecies.

CONCLUSION

Since all the species of mahseer are considered asendangered, special attention from scientist, fishers andentrepreneurs is required in order to protect them from furtherdeclination. Mahseer conservation plan should be an integralpart of the new hydel projects that are in the pipeline in theHimalayan region. The scope of breeding mahseer artificiallyand culturing in ponds should be properly utilized. Thepotential of the species as a cultivable and sport fish has tobe exploited with further research and planning, keeping aneye on their conservation. At least one large size hatchery isrequired to be established in all Himalayan states, which


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possesses mahseer resource. Efforts must be made to breedmahseer species on a large scale. Once the seed is available,state fisheries departments and fish farmers can use fry andfingerlings for hillstream aquafarming, river ranching,raceway ponds and running water culture. Introduction ofmahseer in aquaculture will be excellent for increasing thespectrum of new potential fish species under culture system.There is need to change the present regulation of not allowinganglers to fish in major spawning season since fishes areextremely vulnerable to destructive ways while ascend forspawning. Local people should be allowed to catch fish fortheir livelihood by using line and hook, noose and cast netsand use of other illegal methods should be punishable. Moreresearch and monitoring of the potential streams and riversare needed to strengthen knowledge about the fish in thecontext of recent climatic variation and adaptations. Thus, ifthe suggested remedial measures are implemented in stagesthe mighty mahseer of India can be restored to its glory.Conservation of fish genetic diversity is not only importantfor sustainable fishery but also it plays important role inNational development. Proper taxonomic identification usingdifferent molecular markers is an essential step towardsconservation of endangered mahseer.

The nations who have ratified the Convention onBiological Diversity (CBD) are required to inventorize andmonitor their own biodiversity and biological resources.Poorly studied freshwater species with conservationsignificance must be studied and documented immediatelywith special emphasis on mahseer. Ecotourism can be blendedwith mahseer angling to generate more revenue vis-a-vis toconserve beautiful Indian mahseers. The efforts taken by theearlier workers especially the non-Indian anglers and fisherybiologists, to study this group in a comprehensive mannerhave to be gratefully acknowledged. It was their studies,which have laid the strong foundation of mahseer researchin India. It is expected that collaborative research programmeon mahseers involving different conservation agencies(National Biodiversity Authority, Bombay Natural HistorySociety, Wildlife Institute of India, Zoological Survey ofIndia, Ministry of Environment and Forests, Directorate ofRiver Conservation) will certainly give more comprehensivedata with respect to conservation of these valuable biologicalresources.

ACKNOWLEDGEMENTS

The authors are grateful Dr. S. Ayyappan, Director-General for the support and encouragement.

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The conservation measures are broadly classified into in-situ programmes which protect and manage animalpopulations within their natural habitats and ex-situconservation programmes which remove individual animals,their gametes or embryos from wild populations for captivebreeding as in the case of cryopreservation of gametes (Rall,1985). Maintenance of a species in live gene banks has twomajor drawbacks, viz. they offer no long-term guarantee ofthe genetic stability of the population or species over timeand it is very expensive to maintain the desired representativegenetic information of a population or a species (Rana, 1995).Cryopreservation of gametes is one of the important ex situmethods of conservation of germplasm, and FAO hasendorsed it as a major strategy for conservation of fishresources (Khoshoo, 1997). Cryopreservation of gametesaims to increase the longevity of gametes for several yearswithout any drastic change in the fertilizing capacity of thegametes by lowering the temperature and thereby reducingtheir metabolic rate. Even though the need forcryopreservation of fish eggs and embryos assumes a lot ofsignificance in the light of the role played by themitochondrial DNA, so far the attempts have met with no orlimited success (Hagedorn et al.1997; Ahmmad et al. 1998;2002, 2003(a,b), 2004). However, studies on thecryopreservation of invertebrate eggs, embryos and larvaehave met with some success (McAndrew et al. 1993; Diwanand Kandasami, 1997)

The cryopreservation of fish spermatozoa has been asuccess story so far. Sperm cryopreservation protocols areavailable now for over 200 species of finfish and shellfish(Horton and Ott, 1976; Legendre and Billard, 1980, Kerby,1983, Leung and Jamieson, 1991, Holtz, 1993 McAndrew etal. 1993; Lakra, 1993; Billard et al. 1995; Diwan andNandakumar, 1998; Lerveroni and Maisee, 1998, 1999;Horvath, et al. 2000, Chao and Liao, 2001; Huang andTiersch, 2004). A few sperm banks for fin fishes have beencreated, notably for groupers, salmonids and a fewcommercial and endangered fish species (Chao et al. 2002,Rana, 1995; Ponniah, 1998a). The cryopreservation of fishspermatozoa has many potential applications, likeconservation of endangered fish species by establishinggenetic material reserves for selective breeding, evolvingdesired genotype through cross-breeding, easy transportationand time-independent distribution of genetic material fromone area to another. to produce fish seed in species withdifferential maturity with respect to sexes, seed productionin fish species which are sequential hermaphrodites and tohelp in reducing the cost by eliminating the need formaintenance of the male broodstock in hatcheries (Rao,1989).

Cryopreservation of fish spermCryopreservation is a process where cells or whole tissues

are preserved by cooling to low sub-zero temperatures,


Cryopreservation of fish gametes and embryos

A D DIWAN1, S AYYAPPAN1, K K LAL2 and W S LAKRA2

1Fisheries Division, Indian Council of Agricultural Research (ICAR), KAB II, Pusa, New Delhi2National Bureau of Fish Genetic Resources (ICAR), Canal Ring Road, P.O. Dilkusha, Lucknow, Uttar Pradesh 226 002 India

ABSTRACT

Cryopreservation of gametes is one of the important ex situ methods of conservation of germplasm and has wideranging applications in aquaculture and fisheries management. Though sperm cryopreservation has been a success infishes, yet developing successful protocols for eggs and embryo cryopreservation still remains elusive. Despite successfulsperm cryopreservation protocol known for more than 200 fish species, the adoption of the technique at commerciallevel for fish seed production has been limited. High degree of variability in the procedural requirements and successnot only between the species but at times within the species, is considered one of the limiting factors in its utilization.The present paper records the status of gamete cryopreservation in fish species. The paper provides a comprehensivereview of various aspects of milt cryopreservation such as milt collection, sperm quality and viability assessment,extender compositions, cryoprotectants equilibration periods, freezing rates, thawing of cryopreserved milt andfertilization of eggs and ultrastructural studies on damages in cryopreserved spermatozoa. The paper also provides abrief review of cryopreservation of fish embryos and embryonic stem cells.

Key words: Cryopreservation, Egg, Embryos, Fish, Sperm

110 DIWAN ET AL. [Indian Journal of Animal Sciences 80 (4) (Suppl. 1)

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typically to –196°C (the boiling point of liquid nitrogen). Atthese low temperatures, any biological activity, including thebiochemical reactions that would lead to cell death, iseffectively stopped. However, in the absence of vitrificationsolutions, the cells being preserved are often damaged duringfreezing to low temperatures or while thawing to roomtemperature. Phenomena which can cause damage to cellsduring cryopreservation are solution effects, extracellular iceformation, dehydration and intracellular ice formation.Solution effects are caused by concentration of solutes innon-frozen solution during freezing, as solutes are excludedfrom the crystal structure of the ice. When tissues are cooledslowly, water migrates out of cells and ice forms in theextracellular space. Too much extracellular ice can causemechanical damage due to crushing, and the stressesassociated with cellular dehydration can cause the damagedirectly. Nevertheless, while some organisms and tissues cantolerate some extracellular ice, any appreciable intracellularice is almost always fatal to cells. Vitrification providesbenefits of cryopreservation without the damage due to icecrystal formation (Stoss, 1983).

Due to several anthropogenic alterations and consequenthabitat and environmental degradation, several animalspecies are under threat. The scenario is not only limited toterrestrial ecosystems but similar conditions also prevail inaquatic ecosystems. There is a need for conservation of fishpopulation and sustenance of aquatic biodiversity. Gametecryopreservation is a powerful ex situ conservation toolbesides its wide ranging applications in aquaculture. Undercooled conditions, gametes can be preserved up to severalweeks (short term preservation) and in frozen form, for yearstogether (Long-term preservation). To maintain their viabilityfor longer periods, gametes need to be cryopreserved. It isreported that under optimum cryopreservation and storageprotocols, the viability of gametes can be preserved up to32,000 years (Ashwood-Smith 1980). Polge (1980), for thefirst time, reported the cryoprotective action of glycerol andobserved that fowl spermatozoa retained full motility afterfreezing and thawing in the presence of glycerol. Blaxter(1953) reported the first successful fertilization of herringClupea herrengus eggs with cryopreserved spermatozoa.Sherman (1954) protected the spermatozoa using glyceroland emphasized the importance of rate of freezing andsuggested a method of slower freezing using dry ice.Successful cryopreservation of semen of higher animals likecattle, led to similar attempts to cryopreserve fishspermatozoa. Since then, considerable work has been carriedout with special emphasis on temperate fish species likesalmonids (Horton and Ott, 1976; Holtz et al. 1977; Stossand Holtz, 1981, Lahnsteiner et al. 1996a,b, 1997,Lahnsteiner, 2000).

Regarding tropical and sub-tropical fish species, asignificant progress has been made in the last two decades(Lakra and Krishna, 1997). Several researchers have worked

on the cryopreservation of spermatozoa of fish species, likesilver carp (Hypophthalmichthys molitrix), bighead carp(Aristichthys nobilis), common carp (Cyprinus carpio),grasscarp (Ctenopharyngodon idella), Puntius gonionotus, rohu(Labeo rohita), grey mullet (Mugil cephalus); Pangasiussutchi and in several marine fishes (Sin, 1974; Chao et al.1975; Moczarski, 1977; Withler, 1982; Billard et al. 1995;Legendre et al. 1996; Lahnsteiner; 1996, a, b; Suquet et al;2000 and Diwan and Nandakumar, 2000).

Early attempts on short-term storage of spermatozoa ofIndian Major Carps (IMC) were made by Jhingran (1982)who observed that milt maintained in Ringer-glycerinsolution at 28ºC retained the fertilizing ability for 4 hours.At present, sperm cryopreservation has been successful forseveral finfish species. However, the fish spermcryopreservation needs development of species-specificprotocols. Such protocols are developed throughexperimental standardization of various parameters, after thecaptive breeding protocol is developed. But there is abottleneck due to protracted breeding season and lowdomestication in most fish species. In all such cases, the timeavailable in a year for conducting the experiments is smalland determined by breeding cycle of the species in question.Therefore, it is essential that candidate species for spermcryopreservation be prioritised.

Success of induced breeding mainly depends onavailability of ripe males and females. Sometimes we do notget mature male fishes or get less quantity of sperm evenafter hormonal stimulation. Thus, the milt in these cases, isgained by extracting it from testis cut into small pieces andextended in a saline solution (Legendre et al. 1996). The useof intratesticular sperm causes further difficulties. Males haveto be sacrificed for the collection of testis by surgicaloperation. Sperm obtained from testis may still not beadequate because of reduced volume or poor quality.

As per protocol, fish sperm cryopreservation needs adiluent with cryoprotectant and commonly stored in 0.5 ccFrench medium straws. At the time of fertilization, the strawsare thawed rapidly and poured directly over the eggs tofertilize. The fertilized eggs are raised in the appropriatehatchery. However, there are species-to-species variationsthat are overcome through optimization. Successful methodsfor Cryopreservation of catfish sperm has been reported forseveral species, Silurus glanis (L) (Linhart et al.1993),Chanel catfish Ictalurus punctatus (Guest, 1973), Pangasiussutchi (Withler, 1982); P. hypophthalmusthus (Samorn andBart, 2003), P. larnauduei (Samoran and Bart 2006). Horvathand Urbanyi (2000) reported successful cryopreservation ofC. garipinus, P. gigas sperm has been cryopreserved andthawed sperm were used to fertilize eggs of different species,viz. P. hypophthalmusthus (Mongkonpunya et al.1992), andClarias macrocephalus (Mongkonpunya, et al. 1995). Ritar(1999) carried out artificial insemination studies withcryopreserved semen from stripped trumpeter Latirs lineata

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and reported that fertilization and larval hatch rates weremostly lower for frozen thawed than for fresh semen, higherfor semen frozen with a diluent containing DMSO thancontaining glycerol and similar for semen cryopreserved for1 year to recently frozen semen. Yao et al. (2000) carried outlong-term storage of cryopreservation of sperm of ocean pout,Macrozoarces americanus indicating changes in motility,fertility and ultrastructural changes. In their findings, theyhave reported 33% success in fertilization rate with post-thawed semen and the loss of sperm motility during freezeand thaw due to ultrastrusctural changes of sperm, e.g. severeswelling of the mitochondria or dehydration of cytoplasm atthe mid piece. Ohta et al. (2001), while studying cryopreser-vation of the sperm of Japanese bitterling Tanakia limbata,reported that 10% methanol plus 90% foetal bovine serum isa suitable diluent for cryopreservation of bitterlingspermatozoa and that samples should be cooled to –40ºC ata low freezing rate for effective storage. Lakra et al. (2006)established a protocol of cryopreservation of Clariasbatrachus spermatozoa based on chemical and biochemicalparameters.

Milt collection and quality assessmentThe quality of milt used for cryopreservation is crucial

for optimizing post-thaw viability. Milt contamination withurine can be avoided by gentle squeezing to empty the urinarybladder prior to stripping (Harvey, 1983) as fish milt getsoften contaiminated with urine, blood or faeces duringstripping, which alter the composition of the seminal fluidand induce motility of the spermatozoa. This can havedetrimental effects on post-thaw viability (Billard et al. 1995).A number of workers collected milt from mature male fishesby catheterization to avoid contamination with urine andfaecal matter (Alderson and MacNeil, 1984; Rao, 1989;Cabrita et al. 1988). The use of intratesticular spermatozoaobtained after sacrificing the animal are also in practice whensatisfactory milt quantities cannot be obtained by stripping.Inserting a catheter into the sperm duct is not alwaysrecommended as it might result in irritation of the epithelium,bleeding and infection if frequent sampling is done.Moreover, it might not be possible due to the anatomy ofthese ducts or size of the gonopore as in the case of turbot,european catfish (Labbe and Maisse, 1996).

Anaesthetizing the donors (if necessary), wiping the analand caudal fins with a damp towel to remove excess water,rinsing the genital area with sterile 0.85% saline or any othersuitable extender, collection of milt in clean, dry and sterilevials for immediate storage of collected milt on ice are foundto be advantageous (Rao, 1989; Lakra, 1993; Kurokura andHirano, 1980). To avoid the deterioration in milt quality,many workers suggested that milt be kept on ice soon afterits collection (Kurokura and Hirano,1980; Chao and Liao,2001). Collection of milt using several anaesthetizing agentslike Tricaine methane sulphonate (MS-222) (Coser et al.

1984; Piironen, 1993), has also been reported.Evaluation of fish semen quality is essential to judge the

condition of spermatozoa prior to cryopreservation. Thequality of milt decides the success of a cryopreservationprotocol and there are many important semen qualityparameters to be observed, viz. volume, pH, density of thespermatozoa and percentage of motile spermatozoa (Rao,1989).

Estimation of density of spermatozoaSeveral workers have used different types of cell counting

chambers for the estimation of density of the spermatozoain the fish milt samples viz., Neubauer Haemocytometer(Gopalakrishan et al. 1999) and Thoma Cell (Linhart et al.1993) and Burker Chamber (Piironen, 1993). Kruger et al.(1984) estimated the sperm density of milt of common carp(Cyprinus carpio) and tilapia (Oreochromis mossambicus)by Sysmex Microcell counter CC-120.

Spectrophotometric method for estimation of sperm celldensity has been employed by Suquet et al.(2000), Congetet al. (1996), Lin et al. (1996) and Lahsteiner et al. (1997).Lin et al. (1996) during the cryopreservation studies ofmuskeunge spermatozoa, analysed the sperm density byspectrophotometric method at 610 nm after 1:1000 dilutionof milt and used a formula (58.3 x).D + 0.305) × 109 spermcells/ml to calculate the density of sperm cells.

Spermatocrit value has been estimated for a number offish species (Piironen and Hyvarinen, 1983; Ohta et al. 2001;Basavaraja and Hegde; 2004). During a study on correlationand variation of spermatocrit value and sperm density inAltantic cod (Gadus morhua), Rakitin et al. (1999) found apositive correlation between spermatocrit value andspermatozoa density.

Hara et al. (1982) reported the sperm density of milk fishto be 3.6 × 1012 cell/ml. Gupta and Rath (1993) duringcryopreservation of milt of carps, observed that thespermatocrit values ranged from 65 to 75, 75 to 85 and 65 to75 and the sperm cell counts ranged between 2.1 to 2.5 ×107, 3.0 to 3.25 × 107 and 2.0 to 2.5 × 107 cells/ml for catla,rohu and mrigal respectively. Tiersch et al. (1994) duringcryopreservation of channel catfish spermatozoa estimatedthe density to be 2.5–2.8 × 109 sperms/g of testis. Lahnsteineret al. (1997) reported the sperm density of various speciesof salmonid fishes to be 4.9 ±0.6 × 109 sperm cells/ml forrainbow trout, 2.3 ± 0.5 × 1010 sperm cells /ml for browntrout (Salmo trutta var. fario) and 0.9 ± 0.2 × 109 spermcells/ml for Salvelinus alpinus. Ritar (1999) estimated thesperm density of striped trumpeter to be ranging from 5 ×109 to 15 × 109 sperm cells/ml. Gopalkrishnan et al. (1999)during cryopreservation of brown trout spermatozoa reportedthat the density varied from 9.83 to 18.41 × 109 cells/ml.Basavaraja and Hegde (2004) during cryopreservation ofspermatozoa of Tor khudree, estimated the sperm density tobe 7.45 × 106/ml of milt.


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Determination of sperm viabilityDetermination of sperm viability is necessary when

developing a semen cryopreservation method. Fertilisationassays evaluate the fertilising capacity of spermatozoa andare therefore the most reliable quality markers. However,eggs are sometimes limited and hatching eggs, especially inthe Salmonidae, is very time consuming. Alternative methodsfor determination of semen viability are (1) motilityinvestigations in the form of subjective estimations (Billardand Cosson 1992), computer-assisted cell motility analysis(Lahnsteiner et al. 1996a) and analysis of flagellar beatfrequency (Cosson et al. 1997); (2) measurement ofbiochemical parameters, such as ATP level of spermatozoaand leakage of enzymes (Ciereszko and Dabrowski 1996)and parameters of seminal plasma and of sperm metabolism(Fig. 1, Lahnsteiner et al. 1996b); and (3) assays onspermatozoal membrane integrity (McNiven et al. 1992).

Unlike sperm of higher vertebrates, the ejaculated fishmilt has spermatozoa in inactive state and post activationmotility is of short duration varying from 30 to 300 sec indifferent fishes and these become activated the moment theycome into contact with water (Stoss, 1983). Ability of thediluent used for cryopreservation to maintain the spermatozoa

in quiescent state is a critical requirement as activation priorto cryofreezing can result in loss of capacity to fertilize(Leung and Jamieson,1991). In brackishwater and marinefishes the spermatozoa remain motile for a longer durationas compared to freshwater fishes. In majority of thefreshwater fishes, spermatozoa remain motile for 2–3 minutesand in carps it is only for a short duration 30–60 seconds(Rao, 1989). Basavaraja and Hegde (2004) duringcryopreservation of spermatozoa of deccan mahseer, Torkhudree found that 95–100% sperm cells were motile for1–2 minutes after activation with tap water.

Hara et al. (1982) estimated the percentage of motility inmilk fish by picking up fresh milt with a pointed glass rodand by mixing the tiny drop of milt with 3 drops of seawateron the slide and observing under 40× with a microscope.Withler (1982) during the assessment of motility ofspermatozoa, used cover slip and sperm activated by floodingthe sample with distilled water applied to the edge of thecover slip. Ritar (1999), during assessment of motilitypercentage of fresh milt, used 18G needle to pick upapproximately 0.5–1 μl of milt and used a dilution of 1 : 50to 1 : 100 (v/v). Many workers assessed the motilitypercentage of fresh milt by two-step dilution, the final dilution

Fig. 1. Steps in the computer-assisted analysis of sperm motility (Source : Lahnsteiner, 2000)


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being 1 : 1000 (v/v) (Linhart et al. 1993; Cabrita et al.1988).Thakur et al. (1997) and Ponniah et al. (1999) used a pinhead to pick up about 1 : 1 of fresh milt (equated with amicropipette) and mixed with 1, 2, 3 : 1 of activating mediaor dechlorinated tap water to estimate the percentage ofmotility and duration of motility.

A six point qualitative scale of 0–5 based on mass motililtyof spermatozoa was developed to assess the quality of thesemen by Sanchez-Rodriguez and Billard (1977) and hasbeen widely used by many workers (Kumar, 1988; Fabbrociniet al. 2000). Ponniah et al. (1999) scored the motilitypercentage on a 10-point scale at 10% intervals from 0 to100%. Many workers conducted motility assessment studieswith the help of video camera by frame analysis/computer-assisted analysis of motility parameters (Lahnsteiner et al.1997; Toth et al. 1997; Ravinder et al. 1997; Linhart et al.1993; Ohta et al. 2001). Lahnsteiner (2000) used fertilisationassay method while working on salmonids because theydirectly reflect sperm fertilisation capacity, as also computerassisted cell motility analysis method since this providesdifferent motility parameters in a large member of individualspermatozoa.

In fertilisation method, eggs are mixed with fresh orfrozen-thawed semen by gentle stirring and the viability ofsperm is assayed by the number of eggs developed to aneye-stage embryos. In computer assisted cell motilityanalysis, sperm motility is recorded in videotapes and videosections are analysed in a cell motility analysis programmeoriginally developed for mammalian sperm cells.

Rana and McAndrew (1989) used deactivator solution(0.7% NaCl and 0.6%, KCl, pH 8.2) to arrest sperm motilityand only samples with more than 99% deactivatedspermatozoa were taken for cryopreservation. Many workersaccepted only the milt samples with more than 70% motilespermatozoa with forward motility and used them forcryopreservation (Coser et al. 1984; Piironen, 1993;Lahnsteiner et al. 1997). The milt samples with a minimumof 40% sperm motility were used for cryopreservation byLinhart et al. (1993) where as Cabrita et al. (1988) used themilt samples with more than 60% forward motility forcryopreservation.

Cabrita et al. (1988) used propidium iodide for estimatingthe percentage of viable spermatozoa by using flowcytometry. Yao et al. (1987) conducted the sperm viabilitystudies with salmon milt using 1% trypan blue. They usedmilt, phosphate buffer saline (PBS) and 1% trypan blue inthe raio of 0.1 : 1 : 0.1 (v/v). Kruger et al. (1984) estimatedthe percentage of live spermatozoa in the millt of commoncarp (Cyprinus carpio) and tilapia (Oreochromismossambicus) by using eosin-nigrosin stain.

Optimization of milt dilutionIn a study on cryopreseration of milt of tilapia, Orechromis

spp., Rana and McAndrew (1989) observed the optimum

sperm to egg ratio to be 1.40 × 105 sperm cells/egg. Linhartet al. (1993) observed that in case of European catfish, theoptimal sperm to egg raio was 2.4–3.0 × 106 sperm cells/egg. Conget et al. (1996), during the cryopreservation ofrainbow trout milt, maintained an optimum sperm to eggratio of 3 × 106 spermatozoa/egg. Gopalakrishnan et al.(1999), during cryopreservation of brown trout milt, reportedthat the sperm to egg ratio was 3.38 × 107 sperm cells/egg.Linhart et al. (1993) maintained a sperm to egg ratio of 1.8–2.4 × 105 spermatozoa/egg during the fertilisation trials ofcommon carp. Basavaraja and Hegde (2004) reported theoptimum spermatozoa number per egg to be 103 sperm cells.

Packaging materials used for cryopreservation of miltDuring cryopreservation of fish spermatozoa, most of the

workers made use of French straws of 0.25 ml and/or 0.5 mlcapacity, sealable with polyvinyl alcohol (PVA) powder (Haraet al. 1982; Alderson and MacNeil, 1984; Scheerer andThorgaard, 1989; Gupta and Rath, 1993; Tiersch et al.1994Thakur et al. 1997; Ponniah et al. 1998a, 1998b, 1999,Gopalakrishnan et al. 1999; Basavaraja and Hegde 2004).Alderson and MacNeil (1984), during cryopreservation ofmilt of Altantic salmon, used both 0.25 ml and 0.5 ml sizeFrench straws and observed that good sperm viability wasachievable with 0.5 ml straws.

Several workers used screw capped cryo-vials/glassampoules of different sizes, viz. 1.0 ml or 1.5 ml or 2.0 ml(Durbin et al. 1982; Withler, 1982; Coser et al. 1984; Ranaand McAndrew, 1989; Diwan and Nandakumar, 2000; Linhartet al. 1993). Rana and McAndrew (1989) observed that with1.5 ml cryo-tubes, the percentages of fertilisation showedunacceptable levels of variability and hence they used 0.5 mlstraws for further studies on cryopreservation of spermatozoaof tilapia, Oreochromis spp. Kurokura et al. (1984) used 10ml aluminum foil bags (20 mm × 100 mm) in addition to 0.5ml straws. Lahnsteiner et al. (1997), during cryopreservationof salmonid fish species, studied the performance of 0.5 ml,1.2 ml and 5 ml straws with respect to fertilisation percentageand observed that with 0.5 ml and 1.2 ml straws the fertilisationrates were similar and 5 ml straws resulted in a fertilisationsuccess of only about 40% of fresh semen (control). Cabritaet al. (1988) used 1.8 ml flat plastic straws and 5.0 ml macro-tubes in additon to 0.5 ml straws for a comparative study ontheir performance for application in large scale fertilisationand observed that the percentage of fertilisation was low inlarge volume straws (73.2% and 61.9% for 1.8 ml straws and5.0 ml macro-tubes) as compared to 0.5 ml straws (77.4%)during cryopreservation of rainbow trout milt. Ohta et al.(2001) used long, acrylic capillary tubes (110 mm length × 2mm diameter, volume 80μl) sealed with PVA powder at boththe ends after filling.

Extenders used for the cryopreservation of fish spermatozoaAn extender is essentially a solution of balanced salts and


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sometimes, organic compounds. Spermatozoa must be dilutedbefore freezing with a suitable extender. One of the functionsof the extender is to inhibit the osmotic activation of thespermatozoa (Leung, 1991). The extender is based on abuffered physiological saline solutions, originally describedby Borchand and Schmidt (1979). This is because suchbuffered solution resembles the inorganic composition ofseminal plasma of a spermatozoa. Therefore, the compositionof extender differs from species to species. A large numberof extenders with varying chemical compositlion andcomplexity, including those proven successful for cattlesemen cryoprservation and some animal tissue culture medialike, Ringer’s solution, Cortland’s solution, Alserver’ssolution etc., have been tried for the cryopreservation ofspermatozoa of fish. Several simple extenders, isotonic tofish milt, with inorganic salts like Nacl, KCl, CaCl2,NaHCO3, NaHPO4, MgSO4, MgCl2, KH2PO4 and others withorganic compounds like fructose, mannitol, glucose, lecithin,glycine, egg yolk, Bovine Serum Albumin (BSA) have beenused with varying levels of success (Rao, 1989).

Withler (1982) observed that during cryopreservation ofspermatozoa of L.rohita, Puntius gonionotus, Pangasiussutchi, Ctenopharyngodon idella, Aristichthys nobilis andCyprinus carpio, medium 189M gave good results for L.rohita and for C. carpio, medium 251 gave better results butin the case of Pangasius sutchi, the performance of both themedium amd 189M was poor. Durbin et al. (1982) observedthat post-thaw motililty in the NaCl-NaHCO3 extender wasbetter during cryopreservation of spermatozoa of C. idella.Kurokura et al. (1984), during the cryopreservation of miltof C. carpio, used two extenders namely extender-1 andextender-2 and observed that extender-1 gave more eyed eggs(68.6%) as compared to extender-2 (11.0%). Kumar (1988)studied the suitability of seven extenders for cryopreservationof spermatozoa of Catla catla, L. rohita, Cirrhinus mrigalaand Hypophthalmichthys molitrix and reported that egg yolkcitrate and extender-Ma gave better results in terms ofpercentage of post-thaw motility as well as fertilizationpercentage. Gupta and Rath (1993) used an extender withNaCl, KCl, CaCl2 and NaHCO3 during the cryopreservationof spermatozoa of C. catla, L. rohita and C. mrigala. Duringa study on the short-term preservation of milt of C. carpio atlow temperature, Ravinder et al. (1997) used eleven differentextenders namely, KCL, TLP, Cytomix, Mannitol, FPS,Corland’s Fish Ringer (FR), FR+Tris, NAS, TSM and BWWand found that BWW and TLP were the most suitable storagebuffers as the milt stored in these buffers showed nosignificant decrease in percentage of motile spermatozoa upto 24 h upon activation. Lakra and Krishna (1997) duringcryopreservation of spermatozoa of Cyprinus carpio andLabeo rohita, tested seven extenders for their suitability andfound that Tris-egg yolk was the most effective of all andgave higher post-thaw motility percentage (50%) ascompared to other extenders. Ponniah et al. (1998b) used

CC-1 extender during cryopreservation of milt of C. carpio.Ponniah et al. (1999) use the same extender forcryopreservation of Tor khudree milt. They also tested anegg yolk-citrate extender. Ponniah et al. (1999) used fivedifferent extenders composed of various levels of NaCl, KCL,CaCl2.2H2), NaHCO3, sodium citrate, MgCl2.6H2O.MgSO4.7H2O, NaH2PO4.2H2O, glucose, egg yolk,streptomycin and penicillin for the cryopreservation ofspermatozoa of Tor putitora and observed that extenderNBFGR-2 gave higher post-thaw motility of 90% and ahatching rate of 12.1% when activated with diluter-532.Diwan and Nandakumar, (2000), while carrying out studieson cryopreservation of sperms of certain cultivable marinespecies, used nine extenders with different cryoprotectants.They found out of these nine, extenders, use with MarineRinger and physiological saline solution are the bestextenders for long-term cryopreservation studies. Basavarajaand Hegde (2004) used modified Fish Ringer’s solution forcryopreservation of deccan mahseer. Tor khudreespermatozoa. Lal et al. (1999) observed that the potassiumconcentration (KCl @ 1500 mg /100 ml or 201 mM) requiredin T. ilisha to maintain sperm in inactive state is ralativelyhigh as compared to most of the fishes studied.

Cryoprotectants used for the cryopreservation of fishspermatozoaDurbin et al. (1982) used 10% DMSO as the

cryoprotectant for cryopreservation of grass carpspermatozoa and achieved mean fertilisation percentages of32, 51 and 57%. Hara et al. (1982), during cryopreservationof milt of milt of milk fish, used 15% DMSO as thecryoprotectant and obtained fertilisation percentage of 67.5%with milkfish serum as an extender. Withler (1982) used twocryoprotectants, 8% DMSO and 8% glycerol individuallywith extenders 189M and 251 and found that for rohu, 8%DMSO gave better percentage of feritilisation (58% with189M) and for Puntius gonionotus, 8% DMSO with either189M or 251 gave poor percentage of fertilisation (5%).Alderson and MacNeil (1984) protected the milt of Atlanticsalmon with 9% DMSO. Coser et al. (1984), duringcryopreservation of two freshwater south American fishes,Prochilodus sp. and Salminus sp. used 10% DMSO (v/v)and found that the post-thaw motility percentage variedwidely from 1 to 4%. Kurokura et al. (1984) used 15% DMSOas the cryoprotectant during cryopreservation of commoncarp. Kumar (1988) used 8% glycerol individually duringthe cryopreservation of spermatozoa of India Major Carps(IMC) and silver carp. Rana and McAndrew (1989) testedthe suitability of two cryoprotectants, methanol and DMSOin modified Fish Ringer’s solution for cryopreservation ofspermatozoa of tilapia at six concentrations from 5 to 40%(v/v) and reported that 10% methanol was better. Theyobtained widely variable fertilization rates ranging from38.7% to 93.4% on subsequent cryopreservation with 12.5%


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methanol. Scheerer and Thorgaard (1989) used 9.0% DMSOas the cryoprotectant during the cryopreservation of rainbowtrout milt. Young et al. (1992), during cryopreservation ofmilt of summer whiting, tested four cryoprotectants, viz.0.75M glycerol, 0.75M methanol, 0.75M DMSO and 0.75Mpropylene glycol individually, and observed that glycerolgave better results with respect to post-thaw motility(duration of motility-41 min) and gave better results withegg yolk (duration of motility-50 min). Gupta and Rath(1993), during cryopreservation of spermatozoa of IMC, used15% DMSO as a cryoprotectant. Lakra and Krishna (1997),during cryopreservation of carp spermatozoa and catfishesused sperm DMSO and Glycerol individually at 5% and 10%levels as cryoprotectants and found that glycerol gave betterpost-thaw in C. carpio and DMSO gave better post-thawmotility in case of L. rohita and catfishes. Thakur et al. (1997)used 10% DMSO as the cryoprotectant with six extenderesduring cryopreservation of spermatozoa of rain trout. Ponniahet al. (1998a, 1998b), during the cryopreservatioon ofspermatozoa of C. carpio used DMSO as the cryoprotectantat a concentration of 8% or 10% with varying levels ofsuccess. Ponniah et al. (1999) in their study oncryopreservation of spermatozoa of Tor putitora, used twocryoprotectants DMSO and glycerol individually andreported highest hatching percentage of 12.1% with glycerol.Basavaraja and Hegde (2004) used DMSO at three levels,5,10 and 15% (v/v) and observed high post-thaw motility of92% and 98% with 5 and 10% DMSO respectively, while15% DMSO significantly reduced the post-thaw motility.Among the various cryoprotectants used for long-termcryopreservation of sperm of marine fishes like L. parsia, S.siham, M. cephalus and G. oyena, Diwan and Nandakumar(2000), reported that DMSO in combination with MarineRinger and Glycerine are found to be most suitablecryoprotecants. Further, they mentioned that preservativemedia supplemented with addition of oxygen showed highsurvival rate of cryopreserved sperm.

Oxygen enriched environmentsMaintaining sperm cells in an aerobic environments is a

prerequisite for in vitro preservation (Stoss 1983, Billard1988). Studies on rainbow trout (Buyukhatipoglu and Holtz1978), Billard 1981, Stoss, 1983) suggest that the fertility ofspermatozoa can be prolonged when preserved under oxygencompared with air. To ensure high oxygen availability anddistribution to the cells several different approaches havebeen reported. Milt has been stored in polythene bags (Stoss,1983, Billard,1988) or continuously flushed in a moisture-saturated desiccator (Stoss, 1983, McNiven et al. 1993). Bycombining this technique with the use of antibiotics andlowering the storage temperature to 0ºC rainbow trout milthas been successfully stored for 34 days (Stoss, 1983).

The use of perfluorocarbon emulsions (PFC) such asfluosol and FC-77, which were originally used for respiratory

gas transport in human medicine and cell culture (King et al.1989, Lowe 1991) has increased the longevity of poultrysemen under chilled conditions (Rogoff 1985). The use ofsuch inert organic gas carriers, which have a very high affinityfor oxygen, to prolong the viability of fish milt was recentlyreported for rainbow trout (McNiven et al. 1993). In thesestudies rainbow trout milt held over a non-aqueous layer ofPFC (FC-77) in a moisture laden atmosphere at 0ºC remainedviable for 37 days. Similar studies on Atlantic salmon usingfluosol, however, at 4ºC and –4ºC showed that although miltcould be stored for up to 29 and 69 days, respectively, ateach temperature there was no significant advantage overstorage in air at either temperature.

The depth of milt in the storage container, is also reportedto influence the fertility capacity of milt after storage (Stoss,1983). By sampling rainbow trout milt at various depths in atest tube, it has been demonstrated that there is a pronounceddecrease in post-activation motility at depths below 5 mm(Rana, 1995).

Different Equilibration Periods for Cryopreservation of FishSpermatozoaKumar (1988) used a range of equilibration periods from

2 to 30 min during the cryopreservation of spermatozoa ofIndian major carps and silver carp. Many workers did notuse any equilibration time during cryopreservation of miltof may fish species (Durbin et al. 1982; Coser et al. 1984;Ciereszko and Dabrowski, 1996). Gupta and Rath (1993),during cryopreservation of milt of IMC, used an equilibrationtime of 45–60 min. Conget et al. (1996), during rainbowtrout milt cryopreservation used an equilibration of less than10 minutes. Lahnsteiner et al. (1997), during cryopreservationof salmonid fishes, used an equilibration time of 15 min.Lakra and Krishna (1997), during cryopreservation of miltof carps and catfish, used equilibration times of 4, 120 and170 min. Thakur et al. (1997) equilibrated the milt withdiluent on ice for 10 minutes during the cryopreseration ofmilt of rainbow trout. Ponniah et al. (1998a) used anequilibration time of 10 min at 4ºC during cryopreservationof spermatozoa of common carp, Cyprinus carpio.Gopalkrishnan et al. (1999) used an equilibration time of 15min during the cryopreservation of brown trout. Equibrationperiods of 60, 120, 180 min and 70–95 min (in three steps)were used in a study by Ponniah et al. (1999) forcryopreservation of spermatozoa of Tor putitora, and theyobserved higher hatching percentages at an equilibration timeof 60 min. They also reported that there was no markeddifference in percentage of motile spermatozoa between thedifferent equilibration times. Basavaraja and Hegde (2004)used varying equilibration times ranging from 10 to 90 minduring cryopreservation of deccan mahseer Tor khudree andobserved that very high post-thaw motility rates of 92–98%were obtained at 10, 20, 30 min of equilibration and theyalso observed that fertilisation rates were independent of


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equilibration time.

Different freezing rates used during the cryopreservation offish spermatozoaThe freezing rate is the most critical factor affecting the

success of a cryopreservation protocol. If the freezing rate istoo high, there will not be much time for the free water toseparate from the cytoplasm and hence it results in theformation of small ice crystals within the cell which isundesirable as it punctures the cell membrane and themembranes of the cell organelles. On the other extreme, ifthe rate of freezing is too low, it results in the exposure ofthe cell to the concentrated cytoplasm for a long time. It is asort of pickling effect and due to the high salt concentrationand subsequent changes in the pH, the biomolecules in thecell get denatured. Hence, the optimum freezing rate is amoderate rate between the two extremes of the freezing rate(Franks, 1985). The rate of freezing is a very critical factorin freezing experiments and instant immersion in LN2 hasbeen found to cause significant decrease in post-thaw durationof motility (Young et al. 1992).

Many workers have used manual freezing method whichmakes use of freezing the filled straws at different heightsover liquid nitrogen vapours depending on the freezing ratesrequired using Styrofoam containers and racks for placingthe straws. Witheler (1982) froze the glass ampoules filledwith diluted milt by keeping them at a height of 2 cm aboveLN2 surface for 5–10 min. During a study by Alderson andMacNeil (1984), the straws were frozen over LN2 vapoursfor a period of 5 min for 0.25 ml straws and for 10 minutesin the case of 0.5 ml straws and observed that freezing rateshad no effect on post-thaw fertility over a range of 20–140°C/min. Coser et al. (1984) used a method in which the strawswere frozen at a height of 13 cm above LN2 surface for 2minutes. In a study conducted by Kumar (1988), the strawswere frozen by placing them at a height of 2 cm over LN2surface for a period of 2–5 min. Gopalkrishnan et al. (1999)used a method in which straws were frozen over LN2 surfaceat a height of 6–8 cm for 10 min during cryopreservation ofbrown trout milt. Tiersch et al. (1994) employed a protocolin which straws were frozen on a stainless steel traysuspended over LN2 and a temperature of –80°C wasmaintained at the tray and the straws were frozen for 4 min(after a temperature of –70°C was reached) before immersioninto LN2. In an experiment conducted by Lahnsteiner et al.(1997) during cryopreservation of salmonid fishes, the strawswere frozen on a horizontally mounted rack in an insulatedbox for a period of 10 min and used heights of 1.0 cm (finaltemperature reached –130°C for 1.2 ml straws), 1.5 cm (finaltemperature reached –110°C for 1.2 ml straws) and 2.5 cm(final temperature reached –92°C for 0.5 ml straws) over theLN2 surface. Lakra and Krishna (1997), during cryopreser-vation of carps and catfishes, froze the straws below –120°Cover LN2 surface for 10 min. In an experiment conducted by

Ritar (1999) during cryopreservation of milt of stripedtrumpeter, the straws were frozen over LN2 at a height of 4cm for a period of 270 seconds (final temerature reached inthe straw was –120°C). Cabrita et al.(1988) used a rack thatfloated on the LN2 surface for freezing 0.5 ml straws (at aheight of 2 cm above the surface) and in a metallic supportin a closed Styrofoam box for 1.8 ml and 5 ml straws for 10min. Ohta et al. (2001), during cryopreservation of milt ofJapanese Bitterling, studied the effect of freezing rates onthe percentage of post-thaw motility and observed that at afreezing rate of 18°C/min, the post-thaw motility percentage(31.9%) was high at a final temperature of –40°C. Basavarajaand Hegde (2004), during cryopreservation of Tor khudreespermatozoa, froze the straws at a height of 5 cm over LN2for 10 minutes.

Several workers have made use of methanol-dry ice bath(Kurokura et al. 1984) for freezing before immersion intoLN2 for storage. Several others froze the extended milt withcryoprotectant over crushed dry ice (Scheerer and Thorgaard,1989). A technique of pelletization, by dropping specificvolumes of diluted milt over dry ice (solid CO2) which servesto eliminate the need for individual straws as well as servesto freeze the milt was used by many workers (Piironen, 1993;Clereszko and Dabrowski, 1994; Ritar, 1999). Linhart et al.(1993) pellet-froze (pellet volume 40:1) the diluted milt ofEuropean catfish over small aluminium discs placed at aheight of 4 mm above LN2 surface. Ritar (1999) observedthat fertilization rates were lower for milt frozen as 0.25 and2.0 ml pellets (67 and 69% respectively) and higher for 0.25ml straws (75%).

Some other workers have used programmable freezersfor freezing the diluted milt samples of several fish specieswith different programmes and different final temperatureswere attained before immersion into LN2, viz. (Linhart et al.1993; Rana and McAndrew, 1989; Ponniah et al. 1998a;Conget et al. 1996). Ponniah et al. (1998a) observed thatmaximum hatching percentage could be achieved (56.3% ofcontrol) with an optimal freezing termperature of 20ºCwithout ice seeding and with ice seeding, the hatchingpercentage was low (51.9% of control) with an optimalfreezing temperature of –50ºC.

Thawing of cryopreserved miltThe rate of thawing is also a very important step, which

determines the success of a cryopreservation procedure. It isthe reverse of freezing but rapid thawing is preferred.However too high and too low rates of thawing aredetrimental for the cryopreserved spermatozoa.

Durbin et al. (1982) during thawing, transferred the frozenvials over dry ice for 1 hour and then thawed at 20ºC quicklyin a water bath and obtained the highest mean fertilizationpercentage of 57%. Whithler (1982) thawed thecryopreserved milt by swirling the frozen ampoules in tapwater at 29ºC. During the fertility trials for testing the


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viability of cryopreserved milt of Atlantic salmon, Aldersonand MacNeil (1984) thawed the cryopreserved milt at 37–40ºC for 5 sec in a water bath. Kurokura et al. (1984) thawedtwo batches of cryopreserved milt at 23ºC in a water bath.Kumar (1988) thawed the frozen milt by swirling the strawsin tap water at 30ºC in case of IMC and silver carp. Duringfertility trails, thawed milt was applied immediately to freshova and mixed by stirring with a feather and tap water wasadded immediately after the semen was mixed. Rana andMcAndrew (1989) thawed the cryopreserved milt at 40ºC inwater bath for 8 sec and the spermatozoa were activated withequal volume of pre-warmed hatchery water (at 28ºC) andthe contents of single straw/cryotube were mixed with 50eggs, in a petri plate for 3 min before rinsing eggs with excesswater. Scheerer and Thorgaard (1989) thawed the milt at 10ºCfor 30 sec in water bath during the fertilisation trials for thecryopreserved spermatozoa of rainbow trout. Young et al.(1992), during cryopreservation of milt of summer whiting,observed that post-thaw duration was not affected by differenttemperatures of thawing (0ºC, 23–25ºC and 40ºC). Guptaand Rath (1993) thawed the cryopreserved IMC spermatozoaat 38±2ºC in a water bath and obtained higher hatchingpercentages of 30–40%. Linhart et al. (1993) during thefertilisation trials, thawed the cryopreserved milt at 36ºC for20 secondes and reported a hatching percentage of 45.2(hatching percentage for control-70.6%). In the fertility trialsconducted by Piironen (1993) the cryopreserved milt pelletsof brown trout and arctic charr were thawed by immersingthe pellets in 20 ml (10 pellets/20 ml) of 0.12M NaHCO3 at25–30ºC for 10–15 sec. Tiersch et al. (1994) thawed thecryopreserved spermatozoa of channel catfish at 40ºC for 7seconds in a water bath and estimated the percentage ofmotility as well as percentage of fertilisation. During fetilitytrials of the cryopreserved milt of rainbow trout, Ciereszkoand Dabrowski (1996) thawed the cryopreserved milt pelletsin 0.7% NaCl at 23–25ºC for 5–7 sec. Lahnsteiner et al.(1996a,b), during fetility trials, tested different thawing ratesand observed that the optimal thawing was at 25ºC for 30seconds in a water bath. During the fertilisation trails bylahnsteiner et al.(1997) for the cryopreserved milt ofsalmonid fishes, the milt was thawed at 25ºC for 30 secondsfor 0.5 ml straws and at 30ºC for 30 sec for 1.2 ml and 5.0 mlstraws in a water bath. Thakur et al. (1997) thawed the strawsat 1, 4, 5, 20, 32 and 37ºC for 30 sec and at 32ºC and at 37ºCfor 30 sec and at 32ºC for 60 sec and at 37ºC for 5 sec andreported that thawing at 37ºC for 5 sec gave highest post-thaw motility percentages of 70 to 80%. Ponniah et al.(1998b) thawed the straws by briefly exposing them to air at24ºC for 5 sec and then by rapidly immersing the straws in awater bath at 35ºC for 20 sec. Gopalakrishnan et al. (1999)thawed the cryopreserved milt of brown trout by waving thestraws in the air for 2–3 sec and then by immersing in awater bath at 37ºC for 5 sec and the post-thaw percentage of

motility was assessed.Ponniah et al.(1999), during the fertilisation trials for

cryopreserved milt of T. khudree milt, thawed thecryopreserved milt at 37ºC for 40 seconds in a water bath.Linhart et al. (1993) conducted fertility trials by thawing thestraws at 35ºC in a water bath for 110 seconds. Cabrita et al.(2001) thawed the cryopreserved milt at 25ºC in water bathfor 30 seconds for 0.5, 1.8 ml straws and at 60ºC for 30seconds/80ºC for 20 seconds for 5 ml straws. Ohta et al. (2001)thawed the cryopreserved milt at 20ºC for 7 seconds in a waterbath. Basavaraja and Hegde (2004) thawed the cryopreservedmilt of Tor khudree by quickly plunging the straws into acooler box with water maintained at 37±1ºC for 5–10 secondsand obtained high post-thaw percentage of motility of92–98% and obtained a high hatching percentage of 25.7%.

Use of activation / fertilisation solutionThere have been some differences of opinion, among

different researchers about the effect of the ovarian fluid asan activation solution. But it was proven beyond doubt bythat normal ovarian fluid in fact induces sperm motility butthe presence of broken ova progressively suppresses thisability and reduces the success of fertilisation.

Coser et al. (1984) thawed the cryopreserved milt ofProchilodus sp. and Salminus sp. in a solution of 1% NaHCO3or 0.8% NaCl at 40ºC and observed a post-thaw motilityscore of 1 (1–5%) for Prochilodus sp. and a score of 3 (10–40%) for Salminus sp. Rana and McAndrew (1989) usedequal volume of pre-warmed hatchery water (at 28ºC) foractivation of the spermatozoa. Scheerer and Thorgaard (1989)tested the efficacy of three fertilisation or activation solutionsnamely, dechlorinated tap water, buffered saline and bufferedsaline +5mM theophylline during the fertilization trials. Inthe fertility trials conducted by Piironen (1993) it wasobserved that highest percentage of fertilization was observedwhen the fertilization diluent of Billard was used with thethawed milt. Thakur et al. (1997) conducated fertilizationtrials with 1% NaHCO3 and 5ml diluer-532 as activiatingsolutions. Ponniah et al. (1998a) used Diluer-532 (at 123 mg/10 ml) as an activating solution while thawing the straws.Ponniah et al. (1998b) used three activating solution vi., tapwater (pH 7.5), Diluer-532 at 123 mg/10 ml, pH 8.5) and1.5% sodium sulphite (pH 8.5). They observed high motilitypercentage (80%) as well as high hatching percentage (83%–93% as percentage of control) with the activating solution,Diluer-532. Ponniah et al. (1999) used three activatingsolutions namely, hatchery water, Tris-glycine-NaCl in thefertility trials. Ohta et al. (2001) thawed the cryopreservedmilt and used 0.5% NaCl as an activating solution. Basavarajaand Hegde (2004) did not use any activiation solution duringfertility trials in case of Tor khudree.

Biochemical analyses of fish miltPiironen and Hyvarinen (1983) studied the biochemical


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composition of milt of six freshwater teleosts namely,landlocked salmon (Salmo salar var. sebage), brown trout(Salmo trutta var. Lacustris), rainbow trout (Salmogairdneri), white fish (Coregonus lavaretus), Perch (Prcafluviatilis) and Burbot (Lota lota) and observed that glucoseconcentration was five times higher than fructose and fructoselevel was low when compared to mammalian values. Theyreported that glycerol concentration was found to be highand could be used as a cryoprotectant in species with highglycerol values with good results. Piironen and Hyvarinen(1983) centrifuged the milt at 5,000 rpm for 30 minutes andthe supernatant seminal plasma was stored at –40ºC for 1–5months till further analysis and was analysed for total lipids,glucose and fructose by kits of Boehringer Mannheim. Krugeret al. (1984) analyzed the chemical characteristics of milt ofcommon carp (Cyprinus carpio) and tilapia (Oreochromismossambicus) on seasonal basis and collected the supernatantseminal plasma by centrifuging the milt at 7000 rpm for 20minutes. The milt was analysed for inorganic ions, Na, K,Ca, by flame photometer and organic compounds, fructose,galactose, glucose, lactate, cholesterol, total lipids, proteins,urea, puruvate kinase and ATPase measured with standardbiochemical kits from Boehringer Mannhelm. They observedseasonal variations and significant inter-specific variationin the composition except sodium and galactose. Yoa et al.(1987) contrifuged the salmon milt at 850 g for 5 minutes at4ºC and collected the seminal plasma and used for variousbiochemical analyses. They reported that low temperaturepreservation of salmon (Salmo salar) spermatozoa at –80 ºCled to massive loss of sperm proteins into the seminal fluidwhich indicated the damage o the cell membranes duringfreezing, storage and thawing. Lahnsteiner et al. (2000)investigated the seminal plasma composition of threecyprinid species, the bleak (Alburnus), the chub (Leuciscuscephalus) and the zaehrte (Vimba vimba) by qualitative thin-layer chromatography (TLC) and quantitative spectrophoto-metric assay methods. They analysed the organic compounds,monosaccharides (glucose, fructose, galactose and xylose),lipids (cholesterol, fatty acids, phosphotidylcholine andglycolipids) and proteins and enzyme activities and enzymeslike acid phosphatases, a-glucuronidase, proteases andalkaline phosphatase, pH values and osmolarity. Within 15minutes of collection, the milt samples were centrifuged at350g for 10 minutes at 4ºC and the supernatant was collectedand pooled and the analysis were carried out. Lahnsteiner etal. (2000) estimated glucose, fructose, galactose,triglycerides, phosphotidylcholine and proteins. Lin et al.(1996) centrifuged the milt of muskellunge at 12,000 rpmfor 10 minutes at 4ºC and seminal plasma was collected andkept on dry ice and stored at -80ºC till further use. Theyanalysed the plasma for inorganic ions, Na, K, Mg, Ca, PO4and Cl that were estimated by inductively coupled plasmaemission spectrophotometer and protein was estimated byBradford method. Plouidy and Billard (1982) reported that

semen was centrifuged at 3600 g for 20 minutes and thesupermatant seminal plasma was collected and stored at–20ºC and later analysed for pH, ash, cations, phosphorousand proteins and amino acids. Toth et al. (1997) centrifugedthe milt of lake sturgeon (Acipenser fulvescens), at 4ºC andthree aliquots of pooled plasma from nine fishes that wasused for all the analyses. They conducted the quantitativeelemental analysis of seminal plasma for P, K, Ca, Mg, Na,Zn and Cl using inductively coupled plasma (ICP) emissionspectrophotometer.

Ultrastructural studies of cryopreserved spermatozoa of fishafter thawingA number of workers have studied the damages to

spermatozoa due to cryopreservation both by ScanningElectron Microscope (SEM) and Transmission ElectronMicroscope (TEM) and observed that spermatozoaunderwent morphological changes during cryopreservationviz., winding of flagella, loss of flagella, appearance ofverrucosities on the sperm head as revealed by SEM. Teleostsperm is primitive type and typically consist of a head withdense chromatin, flagellar tail and a ring of mitochondria.Fig. 1 exhibit scanning electron micrograph of Indian MajorCarp, Labeo rohita. Structural changes, viz. detachment ofnuclear envelope and plasma membrane from the nucleusand loss of the central doublet as elucidated by TEM havealso been reported (Yao et al. 2000). Lahnsteiner and Patzner(1998) reported a new method for fixation of spermatozoaof freshwater teleosts for electron microscopy consisting ofan unbuffered mixture of formaldehyde-glutaraldehyde andosmium tetroxide. The studied the damage caused by freezingto sperm and embryo of carps by SEM and found that freezingdamage consisted of expansion of head and neck of the sperm.The plasma membrane of the sperm heads in some caseswere also found to be broken. They also observed that theexternal membrane of the tail appeared disrupted and somesperms were even tail-less. During cryopreservation ofgrayling, they studied spermatozoa the fine structural changesboth by SEM and TEM and noted that morphological damagewas observed immediately after dilution of milt with theextenders. After freezing and thawing about 40–50% of thespermatozoa were completely damaged, 30 to 40% changedand only 10–20% showed an intact morphology. Lahnsteineret al.(1996a) studied the ultrastrutural changes caused inspermatozoa of rainbow trout following cryopreservation byTEM. About 20–40% showed intensive signs of swelling ofthe head and mid-piece regions of the mitochondria. Further,they studied the effect/damage caused to the fine structureof spermatozoa due to cryopreservation of rainbow trout andbrown trout by freeze-fracture electron microscopy andobserved that changes were induced in the organisation ofthe plasma membranes of spermatozoa in the form of particlesgrouped in rounded clusters in a chaotic manner and foldingof the plasma membrane as compared to the fresh


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spermatozoa which showed homogenous distribution ofparticles in the plasma membrane. Gopalakrishnan et al.(2000), during a study on changes in spermatozoa of rohuLabeo rohita, observed the damages in head, mid-piece andtail of about 51% spermatozoa immediately after dilution inone of the cryodiluents as revealed by TEM studies. Theelectron microscopic studies on the spermatozoa of commoncarp revealed damages during freezing process likevacuolization of nucleus, loosening of the chromatin andmorphological damages (Fig. 2) like winding of flagella, lossof flagella, and appearance of verrucosities. Yao et al. (2000)studied the ultrastructural changes in spermatozoa of oceanpout (Macrozoarces americanus) following cryopreservationand the observed damages inluded, severe swelling ofmitochondria and dehydration of cytoplasm at the mid-pieceas revealed by SEM.

Cryopreservation Of Fish Embryos And Embryonic StemCellsThough cryopreservation of fish sperm has been

considerably studied using a number of teleosts as models(Linhart et al. 2000), successful cryopreservation of fish eggsand embryos still remains elusive. Several attempts tocryopreserve unfertilised eggs of fish were not successful(Horton and Ott, 1976) due to dehydration problems, becauseof relatiavely large size of eggs and different waterpermeability of membranes (Loeffler and Lovtrup, 2000). Itis stated that storage of zebrafish embryos using propyleneglycol in the liquid nitrogen even or 1 min resulted in damageof mitochondira, disorganisation of ribosomes andplasmamembrane of the yolk syncytial layer (Anchordoguyet al. 1987). There was 100% mortaility of some teleostCyprinus carpio, Labeo rohia and Brachydanio rario)embryos when stored at liquid nitrogen temperature even

for short duration of up to 3 h (Harvey et al. 1983). On theother hand, Zhang et al. (1989) reported successfulcryopreservation of common carp embyros. Nevertheless,these results have not been duplicated. Whittingham andRosenthal (1978) showed that herring embryos did notsurvive after cooling below –10ºC when protected withdimethyl sulfoxide (DMSO; Me2SO).

Considerable studies have been made for the developmentof suitable cryoprotectant and optimum equilibration timefor successful low temperature storage of fish embryos.Zhang et al. (1993) found that methanol was more effectivecryoprotective agent than either DMSO or ethanediol forzebrafish embryo. Methanol was reported to penetrate theentire embyro within 15 min and other cryoprotectantsexhibited little or no permeation into yolk over 2.5 h(Hagedorn et al. 1997). In zebrafish embryo, the permeabilityof the methanol appeared to decrease during embryodevelopment at 22ºC (Zhang and Rawson (1998). Use ofultrasound was reported to enhance the embryo permeabilityin zebrafish (Bart, 2000). However, methanol wasdemonstrated to show a limited degree of penetration intoprim-6 stage of zebrafish embryos, but it did not penetratein the later stage embryos (Liu et al. 2000).

However, DMSO was also reported to be a goodcryoprotectant for medaka (Oryzias latipes) embryos (Ariiet al. 1987). In common carp, the morulae were partiallyprotected against chilling in DMSO and sucrose, half-epibolyin DMSO sucrose and methanol and heart beat stage inmethanol and glycerol (Dinnyes et al. 1998). Using isotopelabelled DMSO and glycerol Harvey et al. (1983) found thatthese solutes permeated into both dechorionated and intact 5h zebrafish embryos.

Ahammad et al. (2003), while working on hatching ofcommon carp, Cyprinus carpio embryos stored at 4ºC amd

Figs 1-2. 1. Scanning Electron Micrograph of Spermatozoa of Labeo rohita (×1800). 2. Transmission Electron Micrograph of SpermHead in Labeo rohita (×33000). (a) Compact and Dense Chromatin (b) Vacuolation in sperm head and loosely packed chromatin indicatingdamage during cryopreservation

2b2a1


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–2ºC in different concentrations of methanol and sucrose,found that hatching performance wast maximum (41%) insucrose at 4ºC. No survival was observed at –2ºC with anyconcentration of sucrose. Further, it was reported that thecombination methanol and sucrose produced best resultsamong all concentrtions tested at both temperatures. Sameworkers (Ahammad et al. 2003, et al. 2004), while studyinghatching responses of rohu embryos at differentconcentrations of cryoprotectants and temperatures reportedthat hatching performance of embryos stored at –4ºCtemperature in combination of methanol and trehaloseshowed the highest percentage of hatch out (72%).Cryopreservation of pluripotent blastomeres and grafting ofthawed cells into recipient embryos to produce chimeras,open an alternate pathway for production of improved strainsof fish and shellfish. Relatively, attempts to cryopreserveinverteberates, especially crustacean larvae, have been moresuccessful than the finfish. In penaeid shrimp, successfulsurvival of thawed larvae has been reported upto freezingtemperature of –10ºC (Diwan and Kandasami, 1997).

Research to develop cell lines, embryonic stem cells andgerm cells, from Indian fishes, and to develop technologyfor cloning has been emphasized in the past (Pandian, 2002).There have been some successful studies in developing cellcultures such as ovarian tissue from immature ovary ofClarius gariepinus (Kumar et al. 2001). Pluripotent cell linefrom sea bream embryonic stem-like cells (SBESI) has beenreported from blastula-stage embryos of the cultured red seabream, Chrysophrys major. In future, development ofexpertise for other tools, like embryonic stem cellspreservation and cloning, need active consideration, toovercome the challenge of long-term storage of finfish eggsand embryos. Embryonic Stem (ES) cells can differentiateto become any tissue in the body (Hong et al. 2000).Successful protocols for grafting of embryonic cells to hostembryos, for germline transmission of desired genome, canbe instrumental in evolving effective programmes forproduction of transgenics and rehabilitation of endangeredspecies. The tolerance towards cryopreservation proceduresand obtaining viable cells after freeze-thaw has been studiedin a few species. The grafting of blastomere transplantationto produce chimera has been successful in goldfish, trout,zebra fish and medaka. Expression of primordial germ cellsof donor into host system, with successful development oflive trout fry has been demonstrated at experimental level.More research in this area may provide simple assays to targetgerm cells, facilitating pure line in vitro culture of primordiangerm cells for grafting into host embryos.

CONCLUSION

The science of cryopreservation is quite new to theaquaculture industry. It commenced with an attempt tocryopreserve sperm mainly with the concept of “gene banks”.Methods to cryopreserve gametes of aquatic animals are less

developed. Although sperm cryopreservation has been donesuccessfully in a number of commercially important aquaticspecies, particularly teleost fishes and shellfishes, thetechnology has not yet reached an advanced level suitablefor commercial application. Unlike those involvingspermatozoa, attempts to cryopreserve fish eggs and embryoshave been unsuccessful.

The limited success achieved in the cryopreservation ofviable eggs, embryos and larvae of higher animals wasattributed to the large size of the eggs and embryos thatinterferes in the penetration of cryoprotectants and uniformcooling during the cryopreservation process. Sometimes, thelarge volume of yolk present in the eggs and embryos tendsto develop crystals while freezing and if damages the internalparts. In shrimp, though the size of the eggs and embryos issmall, the eggs have the tendency to absorb water soon aftertheir release, swell and become activated for fertilisation.After fertilisation, a strong hatching envelop forms aroundeach egg. Therefore, the presence of water and the thickprotective envelope surrounding the eggs are some of thedisadvantages for successful freezing of viable eggs andembryos. Further research to circumvent these aspects is theneed of the hour in paving the way for establishment of FishGene Bank.

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of summer whiting (Sillago ciliata) spermatozoa. Aquaculture102: 155–60.

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Development and application of fish cell lines: a review

A S SAHUL HAMEED

Aquaculture Biotechnology DivisionDept. of Zoology, C.Abdul Hakeem College, Melvisharam 632 509, Vellore Dt., Tamilnadu.

ABSTRACT

Cell culture has become one of the major tools used in the life sciences today. Tissue Culture is the general term forthe removal of cells, tissues, or organs from an animal or plant and their subsequent placement into an artificialenvironment conducive to growth. This environment usually consists of a suitable glass or plastic culture vessel containinga liquid or semisolid medium that supplies the nutrients essential for survival and growth. The culture of whole organsor intact organ fragments with the intent of studying their continued function or development is called Organ Culture.When the cells are removed from the organ fragments prior to, or during cultivation, thus disrupting their normalrelationships with neighboring cells, it is called Cell Culture. In this paper, development and application of fish celllines are discussed.

Key words: Fish, Cell Lines, Stem Cells

Since 1965, some 157 fish cell lines have been establishedwhich represent 34 families of fishes (Fryer and Lannan,1994). A comprehensive list of most fish cell lines developedbefore 1980 has been published (Wolf and Ahne, 1982) andseveral comprehensive reviews of maintenance proceduresand applications of fish cell cultures are available (Sigel andBeasley, 1973; Wolf, 1973; Wolf and Ahne, 1982). Most offish cell lines were derived from freshwater or anadromousfish species. The limited number of reports on the virusesfrom marine fish compared with those from freshwater fishis due to the shortage of fish cell lines derived from marinefish. The studies of marine fish cell lines have developedrapidly in recent years and at least 17 cell lines from tissuesof commercially important marine fish have been reportedsince 1980 (Fernandez et al. 1993).

Studies on fish cell lines carried out abroadGravell and Malsberger (1965) developed first fish cell

line from fathead minnow (Pimephales promelas). Amonolayer culture of fibroblast-like cells was establishedfrom a marine fish (Caranx mate) and its susceptibility topoikilothermic viruses such as FV-3 and IPN viruses werestudied (Lee and Loh, 1975). A cell line designated SP-1was established from tissue of the silver perch, Bairdiellachrysura and this cell line supported the growth oflymphocystis virus from the silver perch (Wharton et al.1977). Fibroblast-like cells from primary culture of the caudalfin of gold fish (Carassius auratus) was cultivated andcharacterized (Shima et al. 1980). Klaunig (1984) developedprimary cell culture from rainbow trout (Salmo gairdneri)

and channel catfish (Ictalurus punctatus). Nine permanentcell lines was established from five species of salmonidsnative to America’s Pacific Northwest and all these cell lineseffectively supported the growth of one or more of thecommon salmonid viruses (Lannan et al. 1984).

Two fibroblast-like cell lines (OL-17 and OL-32) wereestablished from fins of adults of the medaka, (Oryziaslatipes) (Komura et al. 1988). Lu et al. (1990) developedthree new cell lines from different tissues (fin, snout andswim bladder) of the grass carp, Ctenopharyngodon idellaand these cell lines were found to be sensitive to differentfish viruses such as (Rhabdovirus carpio) (RVC), infectioushemotopoietic necrosis virus (IHNV), infectious pancreaticnecrosis virus serotype VR299 (IPNV), chum salmon virus(CSV) and golden shiner virus (GSV) and these cell lineswere refractory to channel catfish virus (CCV), channelcatfish reovirus (CRV) and Chinook salmon paramyxovirus(CSP).

Vallejo et al. (1991) developed active monocyte-like celllines from channel catfish and found that these cell linesmorphologically resemble mammalian monocytes ormacrophages. Collodi et al. (1992) developed methods forthe culture of cells from blastula-stage diploid and haploidzebrafish embryos, as well as cells from the caudal and pelvicfin, gill, liver and viscera of adult fish. A fibroblast like cellline, ZF4, was developed from 1 day old zebrafish embryosand characterized, and this cell line was found to be a usefultool for the analysis of gene regulation in zebrafish (Drieveret al. 1993). A cell line RTL-W1, was developed from thenormal liver of an adult rainbow trout by proteolytic

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dissociation of liver fragments and grown routinely in thebasal medium, L-15, supplemented with 5% fetal bovineserum (FBS) (Lee et al. 1993). A long-term macrophage cellline from the goldfish was established and characterized,which was maintained in culture for more than 2 years(Wang et al. 1995). The macrophage cell line from thegold fish will be invaluable in studies of pathogen/macrophage interactions, the mechanisms of macrophageantimicrobial effector’s functions and the contribution ofmacrophages to the specific immune responses of teleosts.Faisal et al. (1995) developed continuous cell cultures frommarine teleost, Leiostomus xanthurus and identified theoptimal conditions for spot liver cell survival and propagationin vitro.

Ostrander et al. (1995) developed long-term primarycultures of epithelial cells from rainbow trout (Oncorhynchusmykiss) liver and these cells showed three types of cellpopulations. A new stromal adherent cell line, called troutpronephric stroma (TPS) was initiated from a long-termpronephric culture of an adult rainbow trout, and sub-cultured104 times over a period of 4 years (Diago et al. 1995). Thisstudy also described the culture conditions andcharacterization by enzyme-cytochemistry, electronmicroscopy, isoenzyme profile, cytogenetic techniques, andviral susceptibility. Ganassin and Bols (1996) developedlong-term rainbow trout spleen cultures and found them tobe useful for studying the regulation of haemopoiesis andthe functions of specific immune cells in fish. Hong et al.(1996) established pluripotent embryonic stem cell line fromthe medakafish (Oryzias latipes) and these cells were ableto form embryoid bodies under appropriate conditions anddifferentiate into a variety of cell types. A long-term cellline (SHK-1) was developed from the head kidney of Atlanticsalmon (Salmo salar L.) and characterized with respect tophenotypic and functional properties (Dannevig et al. 1997).Bejar et al. (1997) developed a continuous cell line SAF-1from the fin tissues of an adult gilt-head seabream (Sparusaurata) without immortalizing treatments. This cell line wasfound to be susceptible to Infectious Pancreatic NecrosisVirus (IPNV), Infectious Haemotopoietic Necrosis Virus(IHNV) and Viral Haemorrhagic Septicaemia Virus (VHSV).A continuous cell line, designated FG-9307, was developedfrom the gill tissue of the flounder (Paralichthys olivaceus)and was propagated for 96 passages over 3 years (Tong et al.1997). Bradford et al. (1997) established and characterizedcell cultures from fry of Fugu niphobles and eye of F.rubripes. The continuous cell lines SPH and SPS werederived from the heart and spleen tissues of sea perch(Lateolabrax japonicus) and the cell line RSBF from fintissue of red sea bream (Pagrosomus major) (Tong et al.1998). These cell lines were found to be susceptible to fishbirnavirus and IPNV. Ganassin and Bols (1998) developed along-term haemopoietic culture from spleen and these cellsappeared both to produce and respond to an autocrine growth

factor(s). Flano et al. (1998) described the culture conditionsand the phenotypic feature of different types of spleniccultures established from splenic explants of rainbow trout(Oncorhynchus mykiss). A new continuous cell line (GF-1)derived from the fin tissue of a grouper (Epinepheluscoioides) was established and this line was found to besusceptible to different strains of IPNV (AB, SP, VR299 andEVE), Hard Clam Reovirus (HCRV), Eel Herpes VirusFormosa (EHVF) and Grouper Nervous Necrosis Virus(GNNV) (Chi et al. 1999).

Bejar et al. (1999) developed a long-term embryonic cellculture, derived from the commercial fish (Sparus aurata)and these cells were in vitro characterized for totipotencyand transfected with a GFP plasmid for expression studies.Two cell lines susceptible to iridovirus were developed fromgrouper (Epinephelus awoara) kidney and liver tissues andthese cell lines were designated GK and GL for kidney andliver, respectively (Lai et al. 2000). Chang et al. (2001)developed a tropical marine fish cell line from Asian seabass(Lates calcarifer) fry and this cell line was maintained inEarle’s minimum essential medium (EMEM). This cell linehad been found to be susceptible to IPNV, lymphocystis virus(LDV), grouper iridovirus (GIV), grouper nodavirus (GNV),reovirus from guppy (GRV) and reovirus from threadfin(ThRV). Bejar et al. (2002) have developed a long-term stablecell line, derived from embryonic cells of a marine fish(Sparus aurata) which has been characterized for cellproliferation, chromosome complement, molecular markersand in vitro tests of pluripotency by alkaline phosphatase(AP) staining. Four tropical marine fish cell lines have beenestablished from the eye, fin, heart and swim bladder of thegrouper, Epinephelus awoara, and characterized (Lai et al.2003). Kang et al. (2003) have established and characterizedtwo new cell lines from the flounder, Paralichthys olivaceus,fin and spleen. These cells have multiplied well in EMEM,supplemented with 10% FBS and have been sub-culturedmore than 100 times, becoming continuous cell lines. Twocell lines from liver and heart of juvenile pilchards (Sardinopssagax neopilchardus) have been established and the originof the cell cultures has been confirmed by PCR analysis usingprimers designed to be specific for pilchard mitochondrialDNA (Williams et al. 2003). Shimizu et al. (2003) havereported a cell line (WBE) derived from white bass (Moronechrysops) embryos, that has been grown for more than 80passages over 21 months in Dulbecco modified Eaglemedium supplemented with fetal bovine serum. Holen andHamre (2003) have developed a long-term embryonic stemcell like cultures from a marine flatfish, (Scophtalmusmaximus) and has reported the expression of Oct-4 inembryonic cells by immunofluorescence staining. Apluripotent embryonic cell line has been developed fromembryonic stem-like cells of red sea bream (Chrysophrysmajor) blastulae and named SBES1 (Chen et al. 2003b).These cells have shown positive result for alkaline

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phosphatase activity and differentiated into a variety of celltypes by adding all-trans retinoic acid. Chen et al. (2003a)have established pluripotent embryonic stem cells fromblastula stage embryos of sea perch (Lateolabrax japonicus)and named LJES1. These cells successfully expressed GFPreporter gene.

A continuous embryonic cell line has been establishedfrom gastrula-stage embryos of the Japanese flounder(Paralichythys olivaceus) a marine cultured fish, cells werecultured for more than 200 days with 60 passages (Chen etal. 2004). Pombinho et al. (2004) have described thedevelopment and characterization of two new cell lines,designated Vsa 13 and Vsa 16, derived from the vertebra ofthe marine teleost (Sparus aurata). Chen et al. (2005) havedeveloped and characterized a continuous embryonic cellline from turbot (Scophthalmus maximus) and named TEC.A new tropical marine fish cell line (GS), derived from thespleen of orange spotted grouper, Epinephelus coioides hasbeen established and characterized (Qin et al. 2006). Theexpression of GFP in the cells suggests that the GS cell linecan be used as a useful tool for transgenic and geneticmanipulation. Chi et al. (2005) have developed a novelcell line (BB) from the brain tissue of a barramundi,(Lates calcarifer), which had survived viral nervousnecrosis disease. This is the first cell line reported to bepersistently infected with NNV, and would be a useful modelfor understanding the mechanisms of NNV-persistentinfection in vitro and in vivo. Buonocore et al. (2006) havedeveloped a continuous anchorage dependent adherent cellline, named DLEC, derived from early embryos of theEuropean sea bass (Dicentrarchus labrax L.) and these cellsare transfected using liposomes with a commercial plasmidvector containing a reporter gene. Zhao and Lu (2006) haveestablished and characterized two new cell lines from bodymuscle and fins of bluefin trevally, Caranx melampygus, andthese cell lines have been found to be susceptible to IPNV,IHNV, spring viremia of carp virus, viral hemorrhagicsepticemia virus, snakehead rhabdovirus and channel catfishvirus.

Fish stem cellsEmbryonic stem (ES) cell lines are undifferentiated long-

term cell cultures derived from inner cell mass of developingembryos (Evans and Kaufman, 1981; Martin, 1981). Thesecells retain stem cell characteristics and can be induced todifferentiate into a variety of cell types. When introducedinto host embryo, the ES cells can participate in normaldevelopment and contribute to several tissues of the hostincluding cells of the germ line (Bradley et al. 1984). Thesecharacteristics make embryonic stem cell ideal experimentalsystems for in vitro studies of embryo cell development anddifferentiation and a vector for the efficient transfer of foreignDNA into the germ line of an organism (Goossler et al. 1986).In addition, ES cells provide an attractive strategy for the

preservation of biodiversity (Hong et al. 1996). ES cell lineshave so far been limited to mice (Evans and Kaufman, 1981;Martin, 1981; Bradley et al. 1984) and rat (Iannaccone et al.1994). Human embryonic stem cell lines were first isolatedby Thompson et al. (1998). These cells have the potential toproduce any type of cells of the body and can be propagatedin unlimited quantity for clinical applications such as celland gene therapy (Trounson, 2005).

Most attempts to culture ES cells have been based on theoriginal methods established for mice (Evans and Kaufman,1981; Martin, 1981). To prevent differentiation in culture,mouse ES cells have been derived and maintained on feederlayers (Robertson, 1987) in conditioned media (Martin, 1981;Handyside et al. 1989) or in a medium supplemented withleukemia inhibitory factor (LIF) (Pease et al. 1990; Hasty etal. 1991; Wurst and Joyner, 1993) or with LIF-relatedcytokines (Conover et al. 1993; Nichols et al. 1994; Piquet-Pellorce et al. 1994; Yoshida et al. 1994). In mammalianspecies other than mice and rat, however, ES cells could becultured only for a limited period (Sims and First, 1993) ortheir pluripotency could only be partially maintained afterlong-term culture (Sukoyan et al. 1992; Campbell et al.1996). It has been suggested that the differentiation-inhibitingconditions suited for mice do not adequately preventdifferentiation of stem cells in species other than rodents(Anderson, 1992). To develop ES cell lines and gene targetingtechnique in fish, extensive studies have been done in smallmodel fishes, such as zebra fish (Danio rerio) and medaka(Oryzias latipes), because they offer the possibility ofcombining embryological, genetic and molecular analysisof vertebrate development. ES-like cell lines have beenestablished in medaka (Wakamatsu et al. 1994; Hong et al.1996) and zebrafish (Collodi et al. 1992; Sun et al. 1995).One medaka ES-like cell line, MES1, was shown to retain adiploid karyotype and the ability to form viable chimeras(Hong et al. 1998b). Attempts towards the derivation of EScell lines from the zebra fish (Collodi et al. 1992; Sun et al.1995) and medakafish (Wakamatsu et al. 1994) have achievedonly partial success by using feeder layer techniques. Bejaret al. (1999) have derived a long-term embryonic cellculture from Sparus aurata and these cells have been invitro characterized for totipotency and transfected with aGFP plasmid. Chen et al. (2003a) have established apluripotent cell line, LJES1, from blastula-stage embryos ofLateolabrax japonicus and these cells were found to bedifferentiated into different types of cells under the treatmentof retinoic acid.

Another important aspect of piscine cells is their lowestposition in the ladder of evolution, which makes them suitablefor xenotransplantation in mammals (Wright and Yang, 1997;Laue et al. 2001; Wright and Pohajdak, 2001). The islet tissuecalled Brockmann bodies in certain teleost fish like Tilapia,has been shown to restore normoglycemia upontransplantation into diabetic nude mice (Wright and Pohajdak,


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2001). Similarly reversal of streptozotocin-diabetes has beenachieved after transplantation of piscine islets to nude mice(Laue et al. 2001). These reports indicate potential of piscinecells for clinical applications.

Applications of fish cell cultureFish cell cultures have both fundamental and practical

importance. A diversity of questions can be addressed withfish cell cultures. These include applications in biomedicalresearch (Hightower and Renfro, 1988), toxicology (Babichet al. 1986) and basic fish research (Nicholson, 1989), viralisolation (Chi et al. 1999; Chang et al. 2001; Kang et al.2003) and, gene regulation, expression and gene transfer(Driever et al. 1993). The most widely employed applicationof fish cell cultures and, until recently, the rationale fordeveloping most such cultures, is the isolation of fish virusesthat are agents of epizootics of commercially importantaquaculture fish species. The first fish cell line was developedto facilitate the isolation of infectious pancreatic necrosisvirus (IPNV) and other viruses of trout (Nicholson, 1989).Because of the importance of trout and other salmonid fishcultures in North America, Europe, and Japan, this has led tothe development of other salmonid cell lines for similarpurposes. New cell lines from a variety of fish species arebeing used for the isolation and characterization of previouslyunknown viruses.

In addition to serving solely as a means of virus isolation,fish cell cultures are very useful as in vitro models forstudying the replication and genetics of these viruses, theestablishment and maintenance of virus carrier states, theeffects of antiviral drugs, and the production of experimentalvaccines. Also, in vitro culture techniques have been used toinvestigate unique viruses that do not replicate in standardfish cell lines but require highly differentiated cells. Oneexample is viral erythrocytic necrocis (VEN), a viral infectionof the red blood cells of several species of marine andanadromous fish. Although fish red blood cells will notdivide, viable in vitro red blood cell cultures have beenmaintained for several weeks and used in investigations ofthe replication of these viruses and as in vitro models of viralinduced anemia (Reno and Nicholson, 1980).

Primary cell cultures form an increasingly important toolin understanding fundamental aspects of fish immunology(Faisal and Ahne, 1990). Primary cultures have been usedfor studies on the mitogenic response of fish lymphocytes(Faulman et al. 1983), the in vitro generation and detectionof antibody- secreting cells (Miller and Clem, 1984; Kaattariet al. 1986). Macrophage cultures have been used to studyphagocytosis (Sovenyi and Kusuda, 1987), the respiratoryburst (Chung and Secombes, 1988), lipoxin synthesis (Pettittet al. 1989), the formation of multinucleate giant cells(Secombes, 1985), bactericidal activity (Olivier et al. 1986),and association with fish pathogens (Trust et al. 1983).Nonspecific cytotoxic cells, which may be the fish equivalent

of mammalian NK cells, have been defined through cellcultures (Graves et al. 1985; Cleland and Sonstegard, 1987).

Cell cultures are being used to identify fish cytokines andantibacterials. Both classes of products are being used orbeing considered for use in mammalian medicine (Meager,1990; Elsbach, 1990) but are poorly characterized in fish.An interleukin-1 that elicits a response from catfish peripheralblood lymphocytes is produced by a carp epidermal cell line(Sigel et al. 1986). An interferon gamma-like molecule hasbeen detected in the medium of rainbow trout leucocytesstimulated by concanvalin A (Graham and Secombes, 1990).

Fish cell cultures are also being developed as in vitromodels for studying various biological processes. They havebeen used for determining karyotypes and other aspects ofcytogenetics including chromosomal polymorphism andspeciation, chromosome abnormalities, and evolution(Roberts, 1970). They are also finding widespread use instudying cellular physiology. Examples include: organcultures from tilapia, eel and trout pituitary glands forstudying the production of the growth hormone prolactin(Baker and Ingleton, 1975; Benjamin and Baker 1976); carppituitary organ cultures to determine the efficiency ofhypothalamus extracts on the production of gonadotropinand a continuous carp pituitary cell line producinggonadotropin (Benjamin and Baker 1976).

Fish cell cultures are finding application in toxicologyfor evaluating effects of various chemicals, pesticides andindustrial wastes and in the study of carcinogenesis as invitro models for investigating cell transformation by fishviruses, chemical agents, and the interaction of viruses andchemical carcinogens. Also, fish cell cultures are now beingused for studying the immune response in fish, both fromthe practical view of vaccine development and for the studyof the comparative evolutionary aspects of the immuneresponse. Examples include in vitro stimulation of antibodyproduction for basic studies and testing the potency ofvaccines, in vitro models of immunoglobulin synthesis, andthe role of natural killer (NK) cell activities in diseaseresistance in fish (Kaattari and Irwin, 1985).

Cell cultures can be developed to complementrecombinant DNA technologies for the transfer of genes tofish, such as those for growth hormone (GH). Transgenicfish have been created, but the technology for their creationcould be improved (Chen and Powers, 1990; Cloud, 1990;Ozato et al. 1989). In mammals pluripotent embryonic stem(ES) cells can be placed into culture (Evans and Kaufman,1981), where they can be genetically modified (Roberstonet al. 1988). When injected into embryos, ES cells have beenfound capable of developing into a wide variety of somatictissues and the germ line of the adults (Hooper et al. 1987).

Cell cultures are being used to understand the hormonalregulation of fish reproductive cycles. Both pituitary andgonadal cell cultures have been prepared. Primary pituitarycell cultures are being used to study the regulation of


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gonadotropin hormone (GTH) secretion in response togonadotropin releasing hormone (GnRH) (Fahraeus-van Reeet al. 1982; Weil et al. 1986). Also, a carp pituitary cell culturethat releases GTH has been established (Ribeiro and Ahne,1982). Primary cultures of trout steroidogenic testicular cellsare being used to study the regulation of steroidogenesis (Loir,1990) and information about the local control ofspermatogenesis is being obtained with primary cultures oftrout Sertoli cells and germ cells (Loir, 1989). Ovarian folliclecultures have been used to study steroidogenesis (Van derKraak, 1991) and sex steroid secretion (Carragher andSumpter, 1990). The hormonal regulation and morphologicalchanges of fish oocyte maturation can also be examined invitro (Saat and Veersalu, 1990).

Purified viruses for use as vaccines are likely to be thefirst health product to be obtained from piscine cell cultures.Fish viral vaccines are still in the developmental phase(Sindermann, 1990) but large-scale viral production has beenstudied (De Kinkelin and Le Berre, 1979). This requiresscaling up cell cultures, and for this purpose fish cell growthhas been carried out on microcarriers (Nicholson, 1980), ina ceramic matrix (Lydersen et al. 1985) and in suspension(Lidgerding, 1981). Development of an effective vaccine isan impetus for further development of large-scale cell culturestrategies such as those being worked out for mammaliancells (Arathoon and Birch, 1986; Bols et al. 1988).

Another potential product from fish cell cultures isproteins for use in fish reproduction, growth, and health care.These are likely to come from three polypeptide groups:gonadotropins, growth factors, and cytokines respectively.Generally, these polypeptides are too large to be synthesizedchemically. Therefore, the two sources from which they canbe purified are tissues and cell culture systems. With thedevelopment of efficient methods for transferring andexpressing genes, fish cells are just one of a number of cellculture systems that could be used for this purpose. Fish genesfor some potential products have been expressed in bacteria(Sekine et al. 1985; Peters et al. 1989) and yeast (Hayami etal. 1989).

Fish can be a source of proteins for applications in humanhealth care and in the food industry. Currently at least twofish proteins are employed in medicine. Protamine is used toreverse anticoagulation during procedures such as vascularsurgery and cardiac catheterization (Horrow, 1985). Salmoncalcitonin is used to treat Paget’s disease of bone and certainforms of osteoporosis, and, in this regard, is more effectivethan mammalian calcitonin (Wisneski, 1990). In future, otherexamples might be found of piscine hormones, enzymes, orcytokines being more efficacious in human medicine thantheir mammalian counterparts and as a result create a demandfor fish pharmaceutical proteins. Potentially, fish antifreezeproteins can be used in medicine to cryopreserve humanorgans (Fahy, 1988) and in the food industry to preservefrozen foods (Knight et al. 1984). Different methods are

becoming available for producing these proteins, but fishcell cultures have yet to be used, although they would beexpected to perform the appropriate post-translationmodifications correctly.

The possibility of producing human pharmaceuticalproteins from fish cell lines should be considered. An attributeof fish cells that could be exploited is their ability to grow attemperatures as low as 4°C (Plumb and Wolf, 1971; Mosseret al. 1986). A recombinant mammalian protein secreted intothe medium at this temperature is likely to be less susceptibleto proteolytic breakdown than at 37°C. This could aiddownstream processing in batch systems. For this to besuccessful, fish expression vectors will have to be developedthat allow human genes to be over expressed in fish cells atlow temperatures. Only one attempt has been made atexpressing mammalian genes in fish cells, none, in whichthe mammalian genes have been under the direction of fishsequences. Fish cell lines transfected with a human GH geneunder control of the human metallothionein promoterexpressed GH mRNA but not GH (Friedenerich and Schartl,1990).

Studies on fish cell lines carried out in IndiaThe knowledge on the cell lines/culture from fish is fairly

well developed and progressive in the advanced countriesbut the information in this field from India is limited asevidenced in the literature. Most of the works are based onprimary cell cultures not on continuous cell lines, exceptrecent works published by Sahul Hameed et al. (2006) andParameswaran et al. (2006b). Singh et al. (1995) havedeveloped primary cell culture from kidney of freshwaterfish (Heteropneustus fossilis). Sathe et al. (1995) haveestablished and characterized a new fish cell line (with 30passages only), MG-3 from the gills of mrigal, (Cirrhinusmrigala). Sathe et al. (1997) have also developed a cell linefrom the gill tissues of Indian cyprinoid (Labeo rohita). Lakraand Bhonde (1996) derived primary culture from the caudalfin of an Indian major carp, (Labeo rohita). Rao et al. (1997)developed primary cell culture from the heart of Indian majorcarps. Prasanna et al. (2000) initiated cell culture from finexplant of mahseer (Tor putitora). Sunil Kumar et al. (2001)have developed primary cell culture system from the ovariantissue of African catfish and passaged only 15 times afterwhich they ceased to multiply and consequently perished.Lakra et al. (2005) developed two new primary cell culturesystems from fry and fingerling of the (Lates calcarifer).Lakra et al. (2006) developed a new fibroblast like cell linefrom the fry of golden mahseer Tor putitora (Ham).

A continuous cell line (SISK) from kidney of sea bass,Lates calcarifer, has been established and characterized(Sahul Hameed et al. 2006). The cell line was maintained inLeibovitz’ L-15 supplemented with 15% fetal bovine serum.This cell line has been sub-cultured more than 100 timesover a period of 2 years. The SISK cell line consists


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predominantly of epithelial-like cells. These cells showedstrong positive reaction for epithelial markers such ascytokeratin 19 and pancytokeratin. The cells were able togrow at temperatures between 25 and 32 °C with optimumtemperature of 28 °C. The growth rate of sea bass kidneycells increased as the FBS proportion increased from 2% to20% at 28 °C with optimum growth at the concentrations of15% or 20% FBS. The distribution of chromosome numberwas 30 to 56 with a modal peak at 48 chromosomes.Polymerase chain reaction products were obtained from SISKcells and tissues of sea bass with primer sets of microsatellitemarkers of sea bass. Five fish viruses were tested on this cellline to determine its susceptibility to these viruses and thiscell line was found susceptible to MABV NC1 and nodavirus,and the infection was confirmed by RT-PCR and CPE. Thissuggested that the SISK cell line had good potential for theisolation of various fish viruses. This cell line has been shownto be susceptible to bacterial extracellular products. The SISKcell line is India’s first marine fish cell line.

The development and characterization of a new tropicalmarine fish cell line (SISS), derived from the spleen of seabass, Lates calcarifer has been described (Parameswaran etal. 2006a). The cell line was maintained in Leibovitz’s L-15supplemented with 15% fetal bovine serum. This cell linehas been sub-cultured more than 70 times over a period ofone and half years. The cells were able to grow at temperaturebetween 25 and 32 °C with optimum temperature of 28 °C.The growth rate of sea bass spleen cells increased as theFBS proportion increased from 2 to 20% at 28 °C withoptimum growth at the concentrations of 15 or 20% FBS.The SISS cell line consists predominantly of fibroblastic andepithelial-like cells. Polymerase chain reaction products wereobtained from SISS cells and tissues of sea bass with primersets of microsatellite markers of sea bass. Five fish viruseswere tested on this cell line to determine its susceptibility tothese viruses and this was found susceptible to IPNV VR-299 and nodavirus, and the infection was confirmed by RT-PCR and CPE. Further, this cell line is characterized byimmunocytochemistry, endocytotic uptake of goldnanoparticles using confocal-laser-scanning microscopy(CFLSM), transfection with pEGFP-N1, proliferate marker.

A continuous cell line was established from blastula stageembryos of sea bass (Lates calcarifer) (Parameswaran et al.2006b). The sea bass embryonic cells were maintained inLeibovitz’s L-15 supplemented with 15% fetal bovine serum.The embryonic cell line was sub-cultured more than 70passages over a period of 1.5 years and was designated asSahul Indian sea bass embryonic (SISE) cell line. The cellswere able to grow at temperatures between 25° and 32°Cwith an optimum temperature of 28 °C. The growth rate ofsea bass embryonic cells increased as the FBS proportionincreased from 2 to 20% at 28 °C with optimum growth atthe concentration of 15 or 20%. Polymerase chain reactionproducts were obtained from embryonic cells and blastula

of sea bass with primer sets of microsatellite markers of seabass. Four fish viruses were tested on this cell line todetermine its susceptibility to these viruses and this cell linewas found susceptible to IPNV VR-299 and nodavirus, andthe infection was confirmed by cytopathic effect (CPE) andRT-PCR. Further, this cell line was characterized byimmunocytochemistry using confocal-laser-scanningmicroscopy (CFLSM), transfection with pEGFP-N1,proliferate marker (BrdU).

We have established a pluripotent embryonic stem cellline SBES from blastula stage embryos of sea bass (Latescalcarifer) (Parameswaran et al. 2006b). The SBES cellswere cultured at 28 oC in Leibovitz L-15 mediumsupplemented with 20% foetal bovine serum without usingfeeder layer. The ES cells were round or polygonal and grewexponentially in culture. The SBES cells exhibited an intensealkaline phosphatase activity. The undifferentiated state ofthis cell was maintained in the presence of LIF and the cellsexpressed Oct4. On treatment with all-trans retinoic acid,these cells differentiated into neuron-like cells, muscle cellsand beating cardiomyocytes indicating their pluripotency. Thecell line could be transfected with GFP reporter gene. SBEScell line was found to be susceptible to nodavirus and IPNVVR299 fish viruses as evidenced by cytopathic effect andRT-PCR, suggesting its potential for the isolation of fishviruses. This embryonic stem cell line derived from anoviparous fish blastula exhibits several peculiar features ofviviparous mammalian embryonic stem cell lines making itan economically viable substitute for later. The present studyhighlights the importance and potential of piscine ES celllines for stem cell research without evoking ethical issuesand invasive interventions, sparing thus the mammalianembryos.

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