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Research Journal of Applied Sciences, Engineering and Technology 3(4): 304-317, 2011ISSN: 2040-7467© Maxwell Scientific Organization, 2011Received: February 15, 2011 Accepted: March 21, 2011 Published: April 20, 2011

Corresponding Author: J.F.N. Abowei, Department of fisheries and livestock production, Faculty of Agriculture, Niger DeltaUniversity, Wilberforce Island, Bayelsa State, Nigeria

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An Exposition of the Potentials and Utilization of Sustainable Culture Fisheries in Africa

2C.C. Tawari and 1J.F.N. Abowei1Department of Biological Sciences, Faculty of Science, Niger Delta University,

Wilberforce Island, Bayelsa State, Nigeria 2Department of fisheries and livestock production, Faculty of Agriculture,

Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria

Abstract: The interactions between fish culture and existing uses of floodplain indicate the need to developoverall and integrated management strategies in order to optimize the exploitation of water resources. In acountry where animal protein is an expensive commodity sustainable culture fisheries management isinevitable. This review article is an exposition of the potentials and utilization of water resources in sustainableculture fisheries in Africa particularly in Nigeria. Areas discussed include: Meaning and importance of fishculture, reasons for fish culture in natural waters, relevant physiographical and climatic features fish culturein Africa, development of fish culture in Africa, tilapia culture, cultured species of tilapia in Africa carp culture,culture of other fish species, potential fish for pond culture in Africa, brackish water fish culture in Africa,current status of fish culture in Nigeria, specific composition of managed natural stock, cropping proceduresand productivity species for culture in Nigeria. These exposes the status, potentials and utilization of fisheriesresources in African countries particularly Nigeria. It provides information for management decision indeveloping her economy through the fisheries sector.

Key words: Africa, fish culture benefits, fish species, Nigeria, water resources

INTRODUCTION

The culture fisheries industry is witnessing a fasterrate of development in contrast to the slow pace witnessedin the last three decades (Eweka, 1973). The current trendis as a result of the profitably and feasibility ofaquaculture projects in addition to the increased demandfor fish protein (Ezeri et al., 2009). This has resulted inthe establishment of many fish farms across the world,including both large commercial and small-scale fishfarms. The success or viability of these aquacultureprojects depends among others, regular supply offingerlings of desired fish species to stock the ponds ortanks. However in many instances, farmers do not obtainsufficient number of fingerlings from the existinghatcheries and some times have to source for fingerlingsfrom the wild (Anonymous, 1972).

The economy of riverside peoples in Nigeria is basednot only on activities in the main river channelsbut also, and perhaps more importantly, on the associatedrich alluvial plains or adjacent lands which are floodedregularly, and usually annually, by the river (Ezeri et al.,2009). These annually silted floodplains are locally calledthe “fadama” (Ezenwa, 1974). The contributions of thefloodplains of the Niger-Benue river complex in crop,

livestock and fish production came into sharp focus withthe recent construction of a number of multipurpose damsin Nigeria (Ezenwa, 1974). Because of its location andsize, the Kainji dam on the upper Niger produced thewidest and most dramatically noticeable effects onagricultural and fisheries production of downstream areasfrom New Bussa to the upper reaches of the Niger delta(Sivalingram, 1972). As might be expected, because ofthe contribution of local rainfall to the annual flood, thiseffect of the dam is inversely proportional to the distancedownstream of the dam site (FAO, 2006). It is perhapslargely correct to indicate that the aftermath of Kainji didmore than anything else to direct the attention of Nigerianbiologists and agriculturists to the need for studies aimedat developing management and conservation proceduresfor protecting and maximizing the utilization of majorfloodplains in the country (Hayward, 1961).

Data is scare on the actual number of farmsestablished in the world so as to project on fingerlingsrequirement. However, the demand for fingerlings is over160 billions. This demand is scarcely met and mostfarmers under stock their ponds. The demand for fishfingerlings far exceeds supply, due to lack of commercialhatchery production and from collection from the wild(White, 1973).

Res. J. Appl. Sci. Eng. Technol., 3(4): 304-317, 2011

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To produce one tone of fish (1000kg) under semi-intensive system, 200-2500 fingerlings are needed for a -6 months - grow out period. The current level ofaquaculture production in Nigeria is put at 30,000 tonesannually. To produce 30,000 tones of fish, therefore, 75million fingerlings will be needed. To increase fishproduction to 100,000 tones annually 250 millionfingerlings will be required. If 20% of the land andswamp suitable for aquaculture is to be cultivated, at least3.4 billion fingerlings will be required to stock the pondsat a stocking density of 1 fish/m2 (FAO, 2006).

This therefore underscores the urgency for intensivemass production of fish fingerlings of culture fish species,especially, mud cat fish through establishment of morehatcheries. Fish hatcheries range from small-scale tohyper-intensive systems. Facilities used range from smallwood boxes lined with tarpaulin to intensive indoor waterre-circulatory system using plastic, concrete or fibre-glasstanks. Other hatcheries use water flow-through systems.Major species produced is African mud catfish and theirhybrid using hormone treatment. Notable fish hatcheriesin Nigeria include NIOMR Lagos, Arac, Port Harcourt,Durante Ibadan, Chi Lagos, Barnaly Lagos, ZartectIbadan, And Paiyco Lagos and others.

The constraints to increased fish seed production arenumerous. Scarcity of gravid parent brood stock: Thisproblem can be solved through brood stock developmentand management. Size variation among the fry of mudcatfish leads to cannibalism and low survival. Regularsorting and removal of “Shooters” increase survival rate.Low hatching rate of fertilized eggs. Use of viable eggsand adoption of correct breeding/spawning proceduresincrease hatching rates of fertilized eggs. Highfry/fingerling mortality due to predation in nursery pondsand tanks: Screening of ponds with mosquito mesh andcontrol of unwanted organism will enhance fry survival.Good hatchery management technique will however solvemost of the problems enumerated above thereby ensuringhigher survival rate of fry.

Fish culture classification and facilities depends onthe prevalent economy and soil topography. Adequateknowledge of soil topography culture facilities andclassification bridges the technical language between theaqua culturist and; both surveyors and engineers. Fishbreeding, seed procurement, Hatchery management, fishnutrition, handling, preservation and processing are alsoinevitable vital tools in culture fisheries management andpractice. Aquatic ecosystem, pond and water qualitymanagement are also very essential in culture fisheries.

Culture fisheries, like every other agriculture practiceencounter problems. These may be finance, land tenuresystem, pest and disease. An understanding of the nature,sources, fate and possible ways of controlling them isnecessary for an effective culture fisheries managementand practice. These are basic unavoidable issues needed

in culture fisheries management. The meaning andimportance of fish culture, reasons for fish culture innatural waters, relevant physiographical and climaticfeatures fish culture in Africa, development of fish culturein Africa, tilapia culture, cultured species of tilapia inAfrica carp culture, culture of other fish species, potentialfish for pond culture in Africa, brackish water fish culturein Africa, current status of fish culture in Nigeria, specificcomposition of managed natural stock, croppingprocedures and productivity species for culture in Nigeriaexposes the status, potentials and utilization of fisheriesresources in African countries particularly Nigeria. Thisreview is aimed at exposing the culture, and importanceof fisheries resources to individuals, private companiesand national economy. It can also form the basis formanagement decisions in the management of fisheries,particularly Nigeria and other African countries.

Meaning and importance of fish culture: Fish culture isthe raising of desirable fish species. Fish culture ispracticed in ponds, cages and pens. It permits thesupervision and regulation of reproduction, feeding,growth and control of fish size as well as stocking andmaintenance of fishponds instead of leaving it to nature.Rearing of fish also improves the quality of fish products.Reared fish are intended for food or restocking openwaters such as running and stagnant waters, natural andartificial lakes and ponds.

Fish culture for restocking is different from fishculture for food. The latter is an extension of fish farmingto the production of fish for consumption. Fish culturealso enhances the exploration of ponds resulting in thedevelopment of land, which, otherwise would haveremained unproductive because of too much water, ormarshy land.

Fish is an important component of the total humanand other animal food. It is nutritionally equivalent tomeat in protein with a good amino acid profile, sufficientessential minerals and low in saturated fatty acids.Catches from the wild fluctuates. Therefore, fish cultureis necessary for the steady supply of fish. The fishculturist operates under specific conditions. He should beable to control water quality, ensure proper nutrition,promote breeding and protect fish from diseases andpredators; and consider the economics of its venture.

The advantages of fish rearing over conventionalfishing are many. Fish rearing is more efficient thanhunting because, extensive search efforts are not required.Besides, harvest is proportional to effort and can bepredicted. Environmental conditions can be largelycontrolled and genes can be manipulated to improve yield.Exclusive right to resource can be established in mostcases and international agreement is not necessary.

Fish culture practices can be done on land not suitedfor other agricultural purposes. This means that fish can


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flourish on lands whose waters are mostly saline orbrackish. Fish lives in a fluid medium and are coldblooded. So, they require a minimal metabolic energy formaintenance of body temperature and normal movementcompared to land animals. Therefore, they are efficientconverters of food.

Fish also use space more efficiently than many landanimals, because, they are three-dimensional habitants. Inaddition, the market demand for fish in fish culture can beexpanded more easily than the demand for wild fish. Fishfarmers are able to guarantee the delivery of a certainquantity and quality of fish. This is not always possible inartisan fisheries.

Fish culturist can also control production and markettheir stock when natural supplies are seasonally low orunavailable for other seasons. There is always thepossibility of improving the species by selective breedingto meet consumer’s taste and market requirement. Fishfingerlings collected from the wild include Tilapia sp.(Plate 1), Clarias gariepinus (Plate 2), Heterobranchussp. (Plate 3), Chrysichthys nigrodigitatus (Plate 4), Mugilsp. (Plate 5), Lutjanus sp. (Plate 6), Tarpron attanticus(Plate 7), Lates niloticus (Plate 8), Heterotis niloticus(Plate 9), etc. Shellfish larvae are also sourced from thewild and these include Penaseus notialis,Macrobranchium sp., Crassostrea gasar and others(Mann, 1962).

Collection from the wild is seasonal and unreliablewhereas hatchery propagation of fish seeds ensures allyear-round supply. Fingerlings that are produced inhatcheries in Nigeria include Mud catfish (Clariasgariepinus, Heterobranchus spp., Hybrid of Clariasgariepinus and Heterobranchus sp., Tilapia (Tilapiaguineensis, Orecohrommis niloticus) Common carp(Cyprinus carpio) (Plate 10) and silver catfish(Chrysichthys nigrodigtatus) (Phelines et al., 1973)

Fish culture has become a major income-generatingelement in integrated development programmes. Therecan be a steady increase in fish culture through animprovement of existing technology, the expansion ofculture areas and the development of new culturetechnologies. Most of the present technologies of fishculture in Nigeria are traditional. Although the yield perhectare is usually low. Experience from other countriesindicated that, production levels of existing fish farmingcould be doubled or tripled through the application ofimproved techniques, if the various constraints onexpansion can be solved.

It is believed that an acceleration in the transfer oftechnology, adequate support in credit, training, extensionand other essential infrastructure and; appropriateenvironment and legal management polices are requiredto exploit the potentials of fish culture for self-sufficiencyin fish production. The development of fish culturethrough a variety of methods and under different

Plate 1: Lateral view of Tilapia sp

Plate 2: Lateral view of Clarias gariepinus

Plate 3: D o r s a l v i e w o f H e t e r o b r a n c h u s s p . ,http://upload.wikimedia.org/Wikimedia/commons/2/2acatfishstub-by-malanochromis.jpg

conditions has resulted in many different kinds ofoperations. Various criteria are used in classifying anddefining different kinds of fish culture. Classification anddefinition are necessary because they ensure properconduction of economically efficient assessment andcomparative study.


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Plate 4: Lateral view of Chrysichthys nigrodigitatus

Plate 5: Lateral view of Mugil cephalus

Plate 6: Lateral view of Lutjanus sp.

Fish is cultivated for a variety of purpose. These includethe production of human food for domestic consumptionor export trade, improvement of natural stocks by meansof recruitment and artificial transportation, production ofsport ornamental fish and bait fish for both commercialand artisan fisheries; and the production of industrialproducts such as fish meal, fish feed, fish silage, mincedfish and canned fish. Among these, the production ofhuman food is the most important function of fish culturein any society.

Plate 7: Lateral views of two Tarpron attanticus,http//en.wikipedia.org/wiki/file:Atlantic-tarpon.

Plate 8: Lateral view of the head region of Lates niloticus,http//en.wikipedia.org/wiki/file:Lates niloticus

Plate 9: Lateral views of two Heterotis niloticus duringcourtship

Reasons for fish culture in natural waters: It is perhapsimportant to underline the fact that so far most fisheriesbiologists, both Nigerian and foreign, have tended to holdthe view that fish culture in general is not recommendedor feasible for most areas in the Nigerian Niger-Benuefloodplain. Reasons advanced to support the aboveviewpoint include the high evapo-transpiration rate in themiddle Niger and Nigerian Benue which raises doubtsabout the life span and thus availability of excavated pond


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Plate 10: Lateral view of Cyprinus carpio, http//en.wikipedia.org/wiki/file:common-carp.jpg

water for continuous culture. It is also held that under thepresent conditions, fish culture is unlikely to be profitableand what is more, does not offer scope for significantincrease in fisheries production in the area(Mutter, 1972b). Even the tainting of flavor of culturedfish is advanced as an economic consideration againstculture (Mutter, 1972a). The fact that cheaper capturefisheries have not been fully exploited is also held againstfish farm development.

While it is accepted that some of the factors such asthe availability of water for long periods and the highinputs for artificial farm pond development are importantand valid considerations, the present low level of nationalprotein intake, the fish supply and demand situation aswell as fish consumption preferences of the people ofNigeria inter alia, should receive due consideration, if notover-riding weighing, in decisions regarding thedevelopment of fish culture.

The current demand for fish is about twice the levelof local production from all sources. In many parts of thecountry especially the southern areas, fish may constituteover 40 percent of human protein intake. Indeed, fishforms the dominant source of available animal protein inriverside areas and most parts of the hinterland of thelower half of Nigeria. In the latter area also, the demandfor freshwater fish is very high and people are prepared topay more for this commodity (which also serves forseasoning foods) in preference to cheaper saltwater fish.From longstanding orders for cultured carp and tilapias atGovernment fish culture demonstration farms in bothWestern and East Central States, there is no doubt that theflavor factor is unlikely to be a practical consideration inthe country for a long time to come.

Informed projections on fish production and demandmade at the National Agricultural Development Seminarin 1971 emphasized this shortfall between supply anddemand. Thus while the estimated maximum sustainableyield from all sources was 484 000 metric tons, thedemand for human consumption alone for the target years1975, 1980 and 1985 were 574 000, 830 000 and 1 229000 metric tons respectively. Fish demand for thepreparation of animal feeds was not given.

The indicated wide deficits in fish supply and thepersistence of protein deficiency diseases in the countrycall for immediate mobilization of all available inlandwaters for maximal production. It seems obvious that oneof the readily available paths through which the projectedmaximum sustainable yield can be further increased is byfish culture. While the coordination and other problems ofartificial fish farming, as suggested by FAO (1966), arebeing sorted out by the Federal Department of Fisheries,the cheap facilities for culturing fish offered by theextensive natural residual lagoons, lakes, ponds and poolsof the Niger-Benue fadamas should be put to immediateuse to increase fish production by culture. It is pertinentto note that this line of action is already being pursued ina few of the adjacent river systems in the country. Forinstance, even in the drier and hotter far northern areas,culture trials in fadama lakes is a component of theintegrated development of river floodplains as in theHadejia River Project in Kano State.

Relevant physiographical and climatic features:Considerable data on the present features of physiographyand climate of the Niger-Benue floodplains are given byMutter (1972a, b, 1973). Since the culture media underconsideration are natural lentic bodies of water which arealready in existence, details of such pondfarm limitingfactors as soils, topography, water supply etc. do notrequire extensive discussion here. Therefore, only thesalient features to show the extent and quality of theresource are briefly outlined below.

Niger floodplain: The lower Niger floodplain stretchesfrom the extensive coastal brackishwater areas to theconfluence of the Niger with the Benue at Lokoja . Southof Onitsha, the fadama, 30-40 km wide, is intersected bymany channels with numerous perennial and seasonalponds. From Onitsha to Ida (Fig. 1) the floodplaingradually widens to about 40 km, almost all of this lyingbetween the Niger and the Anambra River to the East.The last stretch of the floodplain from Ida to Lokoja isnarrow with very few perennial ponds. At flow peak, thefreshwater sector from the apex of the delta to Lokoja hasan area of about 6 350 km2 (Mutter, 1973).

Fluvisols are dominant in the floodplain of the Nigerand its tributaries but its complex pattern in the alluvialareas where heavy texture with poor drainage isinterspersed with more sandy and well drained patches isvery important in considering schemes for increasing thesize of natural fadama ponds. Characteristic climaticfeatures include high humidity (60-80%) with meanannual temperature ranging from 26-28ºC. The rainyseason lasts from April to September and causes theheavily silted single annual flood, the “white flood”,experienced in the area. Annual average rainfall variesfrom 2500 mm at the apex of the delta to 1200 at Lokoja(Mutter, 1973).


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Fig. 1: Stretch of the Lower Niger from apex showing mainfeatures of topography

Vegetation cover commences with mangrove swampsof the coastal and deltaic brackish waters, throughfreshwater swamp forests, to riparian forest and savannamosaic at the northern limit. The fadama area of theremaining upper portion of the Niger is generally narrowwith fewer perennial lakes and ponds compared to thelower Niger. It is estimated that up to 5% of thefloodplain may be covered by seasonal and perenniallentic waters. Because of the Kainji dam, the future ofthese lakes and ponds is uncertain.

The area is drier and hotter with average annualrainfall of 1125 mm and annual temperature range of 21-38ºC. The rainy season is from April to October andresults, as in the Lower Niger, in a single “white flood”which peaks usually about September/October. The pre-Kainji siltless “black flood” which used to peak aboutJanuary/February in this area and derived from a prior sixmonths monsoon rains outside Nigeria, has beenobliterated by the Kainji dam.

Guinea savanna dotted with trees and shrubs formsthe dominant vegetation over the entire area and thereforeprovides little cover for natural lakes and pools. Theseconsequently lose more water by evaporation during thedry season than their counterparts in the lower Nigerfloodplain.

Benue floodplain: With the exception of the sector at theCameroon border, the floodplain of the Nigerian Benuewith an area of about 2415 km2 and stretching for about905 km from the frontier to Lokoja, is generally narrow

and has fewer perennial lakes and ponds than the Nigersystem (Fig. 2 and 3). Heavy clay soils with occasionalvertisols in the back swamps predominate. These areseasonally inundated with floods of up to 6 m from Julyto December.

Vegetation and climatic features closely approximatethose of the middle Niger. The climate is warm and humidwith mean monthly temperature and average rainfall of25-30ºC and 1125 mm, respectively. The rainy seasonlasts from March to November with most of the rainfalling from June to October. Scant vegetation cover isprovided by savanna woodland.

Water quality: Very little published information isavailable on the physical and chemical characteristics ofthe Niger-Benue floodplain lentic waters and associatedmain river channels. From Welcomme's (1974) review ofwhat is known of these factors in other African systems,it seems likely that these parameters for the Niger-Benuesystem would approximate the more general Africanconditions.

Such important factors as pH, dissolved oxygen,conductivity and current characteristics of the floodplainsare known to be closely related to the flood cycle.Dissolved oxygen is generally higher in both thefloodplain lentic waters and river channels during thefloods. Conductivity, usually an index of total ionicconcentration, on the other hand, tends to be higher in thedry season than in the wet. Holden and Green (1960) areof the view that the total salt concentration remains thesame but that the lower figures during the flood may bedue to dilution.

The most variable factor between different Africansystems is pH. This variability is thought to be related tosoil factors. However, Holden and Green (1960) observedthat in the lagoons of Sokoto River, a tributary of theUpper Niger, pH tended to alkalinity due to theconcentration of calcium by evaporation.

The existence of water currents on the floodplain,except perhaps during late dry season when the fadamalakes and pools are completely isolated, is a feature whichno doubt contributes immensely to the maintenance of thephysico-chemical qualities of fadama lentic waters andconsequently, their capacity to support the characteristicfish fauna/fisheries of the area.

Fish culture in Africa: The introduction of warm waterfish culture in Africa, with Tilapia, took place between1953-1960. But until that time, fish culture is Africa wascarried out mainly at the subsistence level as a part timeengagement of agriculturalist. The practice of fish farminghad not been done on any appreciable scientific level. Inmost cases breeding and rearing were donesimultaneously in the same pond. Large fish were croppedwhile the total stock was harvested by draining. Many


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Fig. 2: North Eastern State section of the Benue fadama showing narrower width and fewer large perennial lakes and ponds

Fig. 3: Benue floodplain showing mapped fish culture projected production trial

times, fertilization, feeding and weed control wasneglected; this resulted in low yields per unit pond area.

Tilapia remained the most widely cultured fish inAfrica. A total of eighteen species have been tried, butonly a few have stood the test of time. Other widelycultured fish include various species of carp, Heterotisniloticus and catfish. Predators have been introduced tocontrol overcrowding in Tilapia ponds. The mostcommonly used predators include Lates niloticus,Micropterus, salmoides and Hemichronis fasciatus.

Development of fish culture in Africa: Trout hatcheriesappeared to be the earliest practice of fish culture in

Africa, mainly for stocking of spot fishing waters. Theywere established in 1924 at the higher altitudes ofMorocco, South Africa, and Basutoland. Pike hatcheriesfor River and Lake stocking started before World War IIin 1939 in Morocco, while the first and only modern carpfarm was built in 1954 in Panyam, Northern Nigeria. Itwas initially cultured with Tilapia but later changed tocarp production in 1959.

Tilapia culture:Several methods are widely practiced:C The mixed method: This involves culturing of mixed

age classes in which, the same pond is used for both


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Table 1: Yield of Tilapia species with variation in altitude and species utilized in MadagascarS.No. Species Altitude Yield1. T. mossam + T. nilotica Coastal zone near sea level 5 to 6 tons/ha/yr2. T. macrocheir + T. zilli In middle latitude 3.5 to 4.5 tons/ha/yr3. All species Plateau above 1,000m 3 to 3.5 tons/ha/yr4. Only T. melanopleura Above 1,500 2 tons/ha/yrFAO (1966)

Table 2: Tilapia species cultured and countries where they are grown in AfricaS.No. Species Country1. Tilapia macrocheir Cameroon, central Africa, Republic, Brazzaville, Zaire, Gabon, Ivory Coast, Madagascar,

Tanzania, Togo, Zambia2. Tilapia melanopleura Cameroon, Brazzaville Zaire, Gabon, Madagascar, Nigeria, Tanzania, Togo, Uganda, Zambia3. Tilapia mozambicans Brazzaville, Zaire, Mozambique, Rhodesia, Uganda Zambia.4. Tilapia nigra Zaire, Kenya, Mozambique and Uganda5. Tilapia niloticus and T. zilli Most East, Central, and West African Countries6. Tilapia galilaea Central Africa Republic, Cameroon, Brazzaville, Zaire Morocco, Togo, Ghana, Ivory Coast

and CongoTilapia hendolotis Nigeria and Tanzania (Brackish waters)Tilapia aurea Experimental stage in Uganda

FAO (1966)

production and propagation. The pond is stockedwith different sexes, species and age groups ofTilapia. The population propagates and grows rapidlyto a size near carrying capacity of the pond.

C Rearing in age group: The pond is stocked with oneage group. After one reproduction, the pond isemptied, the larger fish are removed and the youngerfish restocked. This method is not very popularbecause production is less than in the mixed method,due to underutilization of the available food.

C Rearing with reproduction control: This methodmakes it possible to avoid the danger of overpopulation using three reproduction checks.

Predators: The commonly used predators includeHemichromis fasciatus, Lates niloticus, Clarias batrachusand Micropterus salmoides (Largemouth black bass). Thismethod is not very successful, as predation can either beinsufficient or total.

Sexing: This involves sexing and stocking only maleTilapia, which grow two or three times the size of thefemale.

Hybridization: If Tilapia honorum is crossed with femaleTilapia nilotica or Tilapia mossambica, a 100% malehybrid results.

Cultured species of tilapia in Africa: Tilapia belongs tothe family Cichlidae and comprises of several species. Itis the most cultured fish in the tropical warm waters inAfrica. Tilapia galilea and Tilapia zilli are indigenous tothe lowlands of Morocco, while T. hendelottis isindigenous to the mangrove areas of Nigeria.FAO (1966), reported that the production of Tilapia perhectare decrease with increase a altitude and varies withspecies utilized in Madagascar as presented in Table 1.

Tilapia mossambica and Tilapia niloticus are mostadequate for brackish water culture. The most widelycultured Tilapia species and the countries where they aregrown in Africa are presented in Table 2.

Fertilization feeding: Experiments at various culturestations have shown that fertilization with commercialfertilizer (N.P.K) can increase yield considerably. Theincrease is attributed mostly to the phosphate component.According to Anonymous (1972), Tilapia ponds do notrespond to fertilization and cow dung as carp ponds. Yieldof Tilapia mossambica, has reportedly been doubled byliming only, but liming before manure application andmineral fertilization in Africa is not recommended.

Intensive feeding with leaves, grass and folder hasproved very satisfactory. For better utilization of availablenatural food such as plankton, mixed culture withherbivorous and microphagous species is recommended.Food conversion ratio of the leaves = 20:1. For aquaticfood and herbivorous species, soft submerged and semi-submerged water-flora is recommended.

Terrestrial food: For herbivorous and omnivorousspecies, all kinds of soft vegetation, household and ruralwaste could be fed. Others are maize, cassava, rice bran,potatoes, rubber seed and groundnut (Peanuts).

Carp culture: Carp were cultured in Africa before 1895and used in the Cape province of South Africa in 1896 tostock natural waters. But it was not until the early 1960’sthat carp culture gained acceptance in Africa. Carp culturestarted in Panyam fish farm in Northern Nigeria in 1959with carp of Yugoslavian and Israeli origin. SomeEuropean strains were introduced in Rhodesian and SouthAfrica in 1958 and 1959, respectively. Carp wereintroduced in Ghana in 1962 from the Panyam fish farmfor experimental purposes, while Uganda started toculture Israeli carp in 1961.


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In the temperature countries, carp mature in the 3rd

and 4th years, but in the warm waters of the tropicalregion, they mature in the first year. In the plateauhighlands of Nigeria, carp have a distinct spawningseason, but in the lower altitude, it spawns and matures atany time.

The most widely cultured species is the commoncarp, Cyprinus carpio, which has gained prominence inZaire, Ghana, Nigeria, Morocco, Uganda and Rhodesia.In Nigeria, an average production of 3,000 kg/ha for carp,Tilapia or catfish plus 500-600 mullet in poly cultureexperiments (with fertilization and supplemental feeding)have been recorded. The principal feed used for commoncarp was groundnut cake and fishmeal at 10% of bodyweight per day. Carp can grow at the rate of almost 0.5 kgper month in warm waters of the tropics.

Culture of other fish species: Heterotis niloticus: This species has received greatattention in Africa because of its rapid growth rate of 2 to3 kg/year. It does not easily spawn in small ponds.Therefore, more than two hectares of pond arerecommended. Breeding occurs all through the year in thelow altitude. Supplemental feeding with rice bran,groundnut cake, and cotton seed cake has produced goodresults. Heterotis has been introduced in Nigeria,Cameroon, Ivory Coast and Madagascar, but wasaccepted with reluctance by consumers, because of itstaste and numerous sharp lancette-sharp bones. It could beraised in home - stead fishponds together with Tilapia.

Largemouth (Micropterius salmoides): Theproduction of the American largemouth black bass hasbeen tired in Zaire, Gambia and Rhodesia in combinationwith the blue gill (Lepomis macrocchirus), but has gainedno economic importance. The fish has reportedly not doneso well, especially as regards propagation in the loweraltitude region of tropical Africa. In the Atlas mountain ofMorocco, propagation in rivers and reservoirs has notproduced satisfactory results.

Lates niloticus: This is produced mainly in fish culturecenters for the control of Tilapia overpopulation.Propagation in ponds has proved difficult, but the fish hasbeen made to reproduce by changing the water level ofthe ponds according to the rhythm of the flood in therivers. Lates need larger water bodies for spawning.

For combined culture, a poly culture of carp andTilapia is recommended, but experiments at the Payamfish farm in Nigeria has shown that over population byTilapia can suppress the growth of carp. Heterotis isnormally raised together with Tilapia satisfactorily. Also,Citharinoides can be grown together with Tilapia. Amixture of carp, Tilapia nilotica and Tilapiamelandopleura or carp, Tilapia macrocheir andHaplochromis mellandi are often recommended.

Potential fish for pond culture in Africa: These include:Chinese carp, Indian carp, Israeli carp, mullet, Tilapia,Anabantidae, Nile perch, Protopterus, Heterotis, Chanoschanos, Stolothrisa, Clupeids, Characids, Catfishes,Cichlids other than Tilapia, Symbrachus, Lepidosiren andother air breathers, trout; and large mouth bass.

The grass carp (Ctenopharyngedon idellus) hasextraordinary ability to ingest great quantities of grass andother vegetation. The by products of ingestion may beutilized directly by other fishes or by consumption ofplankton which arises from faecal decay. The grass carpplays a vital role in pond ecosystem and therefore, hasgreat potential in Africa.

Tilapia zillii eats plants and plankton; and thereforeclears waters. The turnover rate of nutrients with in thepond is accelerated when this plant eater is introduced.This results in higher productivity by decreasing theenergy exchange time. High rates of fish production canexist in tropical waters even though nutrients appear to belimited, because there are many plant eating fishes in thetropics (Phelines et al., 1973).

Fishes, which feed on phytoplankton, are by far themost commonly occurring herbivores. Tilapia esculentahas a feeding mechanism, which adhere plankton bynormal breathing motion with mucous secretion, and thegill rakes prevent the escape of the entangled algae(Olayide, 1966).

Tilapia esculenata and Tilapia variabilis consumediatoms, green and blue-green algae. Tilapia nilotica iscapable of digesting blue-green algae and is quite capableof obtaining large sizes on such a diet. Tilapiamossambica is also capable of good growth but cannotutilized blue-green algae. Epiphytic bacteria or protozoaon the algae were thought to have an effect. Chanoschanos is capable of digesting blue-green algae with well-noted growth rates. Pangasius satchi, which may grow toa length of one meter, feed exclusively on the blue greenalgae, micorcysitis (Mann, 1962).

Epiphytic algae eaters are quite common in the Lakesof Northern Africa. Nineteen species of fish have thisfeeding method. Pangasidon gigas, which reaches alength of two meters, has no teeth and feeds exclusivelyon algae growing on the bottom of Rivers and Lakes.Cirrhinus auratus and Cirrhinus jullieni have been caughtin large quantities and they are all epiphytic algae.Thynnicthys thynnichthys has identical feeding habits andrepresented 15-20% of the total tonnage caught in someLakes. Castlacarpio sjamensis feeds on diatom and canobtain lengths up to 2.5 m (Hayward, 1961).

Africa has several air-breathing fishes as nativespecies. The lung fishes, Protopterus and Polypterus andthe barbel Clarias. (a relative of Clarias batrachus areamong the few native species of fish capable of living inmany Africa’s swamps. The development of the species:Snakehead, Gouramis, Clarias batrachus, the Eel


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(symbranchus), the lungfish (Lepidoiren), Erythrinusunitacniatures, Hypopomus breviriosteris, HaplosterunmLitoreale, the Locricarrid fish (Ancistrus anisisteis) fromother parts of the world as cultured fishes might lead tovery high yields in extremely poor quality water(Ezenwa, 1974).

The potential of aquaculture activities in Africa seempromising. The abundance of water and the great numberof herbivores and several air-breathers allowexperimentation with many mixed fish communities(Eweka, 1973).

Brackish water fish culture in Africa: In most Africancountries, the importance of fish culture has not been fullyrecognized and its development has not been pursued,mainly, because of a lack of fisheries organization and ashortage of professional and trained staff. Anotherhindrance is the small amount of educational material andinstruction booklets related to local conditions. The fishspecies of greatest value in fish culture, in central EastAfrica are all members of the cichlid family. The mostimportant, belong to the genus Tilapia. For the followingreasons Tilapia are highly desirable for use in intensiveculture.

C They are efficient converts of waste food stuffsC They have a short food chainC They can readily adapt to crowded conditionsC They can easily breedC They are generally free from parasites

Five species of Tilapia are of importance:T. melanopleura, T. sparramanni, T. andersonic,T. mossambica and T. macrathea.

In Nigeria, Mullet culture in brackish water ponds isnecessary because:

C Mullet fry tend to congregate in shallow tidal poolsat low tide, where they are caught with very littleeffort.

C They are available throughout the year in these pools,though in greater numbers from March to July thanduring the rest of the year. Two and half million fry(22-50 m) can be collected annually, with 50%mortality during handling.

Attempts are still experimental on how to acclimatizethe fry to pond situation. Poly culture attempts havealready started for mullet, which feed on bottom detritusand the catfish Chrysichthys nigrodigitatus, a freshwaterspecies that feeds on mollusks (Anonymous, 1972).

The first attempt consisted of four ponds having acombined area of 0.82 ha. Salinity varied from 0.5% atthe end of the rainy season in September-October to 20%during the end of the dry season in March-April. The tidal

ranges in ponds were narrow with a maximum of 40 cmduring the latter part of the rainy season. In new ponds,the pH was 4. A year later the pH was 7. For unfertilizedponds the pH was 6.25 and 6.75. Tilapia, C.nigrdigitatusand Mullet have been attempted in poly culture. Yields of957 to 1,159 kg/ha/yr were reported when the fishharvested came in as fish eggs and larvae through thescreen at the gates of the pond. These yields were attainedwithout any form of stocking, feeding or fertilization, andin the absence of predatory species. With feeding andfertilization a yield of 2,200 kg/ha/yr was reported(White, 1973).

Poly culture trials in brackish water ponds in Lagosindicated that natural entry of mullet fry with tide couldresult in production of mullet up to 239 kg/ha/yr inaddition to that of other species which entered along withthe mullet, without supplementary feed or fertilizer.Stocking of mullet fry increased the mullet yield.Experiment indicated that supplementary feed alsoincreased both yield and average size. Predators likeBarracuda reduced Mullet populations in fishponds andalso their yield Sivalingam, 1972).

Current status of fish culture in Nigeria: In thetraditional riverside fishing community in Nigeria, thedevelopment of culture fisheries has lagged behindcapture fisheries. However, fulltime fishermen inpractically all sectors of the Niger-Benue floodplain havefor long realized that the seasonal as well as perennialpools, swamps, lakes and lagoons of the fadama form arich and surer source of fish than river fisheries during thedry season. This had led over the years to local anduncoordinated attempts to convert some of thesefloodplain ponds and swamps into what can be rightlydescribed as extensively managed and largely unfed“culture ponds”. The level of management depends onwhether such ponds are communally or privately ownedalso their distance from settlements or villages(Pillay, 1968).

Privately owned ponds near villages or temporaryfarm settlements are usually partially fed and fertilizedwith agricultural wastes and household sweepings. On theother hand, communal lakes and ponds, whether seasonalor perennial, are unfed.

Niger floodplain: The lower Niger has the best knowncases of partially managed and fed natural fish ponds. Therich triangular floodplain between the Niger and Anambrarivers has over 52 large perennial lakes and ponds, largelyunder private ownership with a total dry season surfacearea of about 1650 ha (Awachie, 1973). The practice ofdumping rice husk and maize wastes from local mills onthe edges of perennial lakes and ponds and even the riverchannels is widespread here. Local farmers, who are alsopart-time fishermen, are aware that this practice helps to


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fertilize the ponds as well as provide fodder forherbivorous fish such as the “river cow” Distichodus spp.and some omnivorous. It is noteworthy that about 70% ofthe fish sold at Otuocha, Onitsha, and Ogrugu during thedry season consist of Clarias, Heterobranchus,Gymnarchus, Distichodus, Ophiocephalus and Citharinusspecies “cultured” in these semi-fed and unfed ponds(Pillay, 1962).

At Atani and Odekpe, south east of Onitsha,supplementary feeds are provided, as indicated above, byhousehold wastes such as dry cassava peels which findtheir way into smaller and continuously cropped familyponds. Here also the construction of temporary dwarfearth dams across outlet channels, not so much to retainwater as to prevent fish from migrating back into the mainriver channel with receding floodwater, is common(Phelines et al., 1973) .

Similar semi-culture but more rudimentary practicesexist all over the Niger delta including brackish waterareas. Unlike in the upstream freshwater areas, thesaltwater zone has mainly perennial lakes and pondswhich are replenished daily by tidal flow. To retain fish,therefore, various combinations of barriers involvingsticks of mangrove and raffia palm as well as wire meshare built round the ponds/pools as necessary. Thearrangement ensures free flow of water with minimal lossof fish (Olayide, 1966).

Benue floodplain: Most of the perennial fadama lakesand lagoons are communally owned and unfed. Indeed, itis perhaps correct to indicate that, traditionally, very littleif any attempts are made to manage these bodies of waterto improve their productivity (Mann, 1962).

Specific composition of managed natural stock: Fieldinterviews with fishermen do not seem to indicate thatstocking of fadama lakes and ponds is a long standingpractice. The stocking of backyard natural ponds withfingerlings of various fish, especially clariid species,taken along temporary barriers across receding floodwaters and observed during 1965-1974 in theAtani/Odekpe and Oguta areas of the lower Niger, wouldappear to be a relatively recent development dating backto about only six to seven generations (Hayward, 1961).

The species managed and/or semi-cultured are, fromthe above indications, those which (as traditionalfishermen are fully aware) are hardy to handle and arenaturally adapted to surviving in such bodies of water.These species include those which seasonally undertakelateral migrations to the inundated fadama pools andswamps which serve as breeding and nursery grounds.The dominant elements are catfishes such asHeterobranchus, Clarias, Synodontis, Chrysichthys,Malapterurus, as well as others such as Polypterus,Protopterus, Gymnarchus, Heterotis, Xenomystus etc.which are known to possess suitable adaptive features for

living under low oxygen conditions of floodplain lenticwaters during the hot dry season. Common but minorelements in such ponds include some cichlids especiallySarotherodon (=Tilapia) and Hemichromis, citharinids,cyprinids, mormyrids and characids (Ezenwa, 1974).

Cropping procedures and productivity: Large lakes andponds whether private or communal, are harvestedannually, usually at the dry season when catches from themain river channel are very poor. It is often the practice ofmigrant fishermen to purchase fishing rights of privatelyowned ponds and then crop them under agreed terms. Dryseason communal fisheries activities in both unfed andsemi-fed fadama lakes and pools have led to thedevelopment of annual “fishing festivals” which are fastbecoming a tourist attraction. Indeed, the Argungu fishingfestival on the floodplain of Sokoto River is today anevent of some international significance (Eweka, 1973).

Smaller semi-fed family ponds are subjected tocontinuous cropping to meet household requirements. Themode of cropping is related to the topography, as well asthe nature, size and depth of the “pond” and shows localvariations.

In the few completely harvested ponds, which areusually purchased ponds, water is either evacuated bymeans of hired pumps or by cutting shallow canals as ismore normally done in the lower Niger. In swamps andpools, the canals are usually very long and often blind.Stranded fish as well as those that move into the canalsare easily picked up. Welcomme (1971) has described avery similar procedure for the Oeine River floodplain inDahomey.

Larger fadama lakes and lagoons are cropped with allavailable gear ranging from local traps, weirs andscooping gear to gill and cast nets as well as long lines.As might be expected, these larger perennial bodies ofwater are never completely fished out. From theforegoing, it can be readily appreciated that althoughthese natural ponds are rich, their mode of exploitationhas made any reliable assessment of their yield almostimpossible. It is hoped that data from experimental naturallakes and ponds in the Atani/Odekpe area and Do-Anambra floodplain will provide some useful indicationof their productivity (Eweka, 1973).

Species for culture in Nigeria: Both local andacclimatized exotic species which have proved successfulso far in the country will be utilized. These species are themain stay of tropical fish culture, viz.: tilapia and carp.Their fry and fingerling supply problems are well knownand a number of farms now produce their fry for saleEzenwa, 1974).

Particular effort will be made to use those localspecies which naturally inhabit the media to be employedfor culture and which were listed above. It is also


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noteworthy that a number of these species are currentlybeing developed for culture. Those which have showngreat promise and may be described as even popular infreshwater ponds include Clarias spp., Heterobranchusspp., Heterotis niloticus, Chrysichthys nigrodigitatus,Lates niloticus, Gymnarchus, and to a lesser extentCitharinus spp., (Hayward, 1961).

The culture drawbacks of tilapias via liability toprecocious breeding and consequent rutting can be turnedinto a cultural advantage by cropping tilapia farmscontinuously as is the practice in intensively managedfarms in Western Nigeria. Also, fast breeding tilapias canbe reared as trash fish either in mixed or poly specificculture with highly-priced carnivorous fish such as Latesniloticus or Gymnarchus niloticus; alternatively, they canbe reared in mono specific culture and then used to feedthe latter species (Mann, 1962).

In the brackish water areas of the Niger delta, readilyavailable euryhaline species, apart from tilapias, areC. nigrodigitatus and the mullets especially Mugilfalcipinnis. At the moment the fry/fingerlings of thesespecies are collected from natural sources - the fadamaand brackish waters (Olayide, 1966).

DISCUSSION

It could be inferred from the foregoing discussionthat although fish culture in Africa has not progressed aswould be expected, there exists a great potential for itsdevelopment with more intensive research, improvedmanagement practices, better extension serviceprogrammes and better infrastructure for large scalecommercial fish culture. Fish farming in Africa is sure toassume greater importance in the economy of the Africannations. With production increment beyond the presentsubsistence level, more people would be attracted intocommercial fish culture business. Above all, there arepresently large hectares of swamps, lagoon, and naturalbodies of water, which have not alternative uses. Thesecould be utilized for large scale, commercial fish culturesoperation. Such would not only contribute considerably tothe economy of the region, but would improveappreciably the protein consumption level of the presentlyundernourished masses of the continent (FAO, 1966).

As can be readily surmised from the foregoing, themain bodies of water to be involved are suitablefloodplain lagoons, lakes, ponds and pools alreadyexisting in natural depressions as well as swamps fringingthe main river channels. To be included also are swamprice fields with a suitable level of water for a desiredperiod. The above will provide the mainstay of fishculture in natural waters.

As an important supplement to the above, natural aswell as artificial human water supply reservoirs and eventhe flood control reservoirs projected for the Niger-Benue

system, will be harnessed for fish culture in the presentcontext. Depending on their life span and the length oftime they are available for fish culture during the floodcycle, the above media may be utilized as seasonal orperennial farms (Phelines et al., 1973).

Field trials at Atani on the lower Niger floodplainduring 1968-70, when other fish culture farms in theformer Eastern Nigeria were unavailable because of thecivil disturbances showed that by skilful management ofthe fadam floodwater it is possible to culturefry/fingerlings to the harvest stage under almost purelynatural conditions (Awachie, 1968, 1969, 1973). Fry andfingerlings collected with the aid of a task force ofexperienced local fishermen from receding floodwaterwere used in stocking the main types of natural waterschosen for the trials viz.: floodplain ponds at Atani, a cut-out lake in the hinterland, and kraals or fish-pens at theperiphery of Oguta lake, Njaba and Idamili Rivers(Pillay, 1962).

To collect sufficient fry/fingerlings quickly andsafely, earth-backed palm frond barriers were erectedacross minor receding channels and along the edge ofshallow flooded pools or selected areas of the floodplain.Fingerlings and fry were then readily scooped into allavailable containers. Large calabashes and open tins weremost commonly used in delivering fish to desiredlocations. About 50% of cultured specimens came fromtraditional “fry fisheries” which involve large locallymade lift devices as well as lift nets installed at the river-sides as floods recede, and used to lever out largenumbers of mixed fry/fingerlings from grassy river orpool edges. The main sources of fingerlings after floodrecession were the smaller floodplain pools which weresurrounded with small earthwork during late flood phase(Pillay, 1968).

Two ponds, 0.6 and 1.5 ha, respectively, convenientlylocated near the task force fishermen's homes and almostencircled by dwarf earthwork as the flood receded, wereleft unfed for five months and then harvested. Theaverage yield was 250 kg/ha with clarids, mochocids andgymnarchids being the dominant fish. On stocking thesame ponds, each with 1 000 Clarias fingerlings and 1 000cichlid fry and fingerlings from nearby ponds, the yieldafter six months with very little feeding was 657 kg/ha.The harvest included Synodontis spp., Hydrocyon spp.and Notopterid spp., (Anonymous, 1972).

Because of extensive poaching activities caused bywartime conditions, it was not possible to quantify withreasonable accuracy the yields from the partially-fedhinterland lake and two kraals stocked with Clarias spp.and Tilapia spp. tilapia and carp; and Parophiocephalusspp. respectively. However, the estimated yield from thelake varied from 900 to 2 060 kg/ha/yr. It may also bepointed out that because of widespread acute shortage ofprotein during the period, the then Head of the Fisheries


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Operations (the present author) was inevitably moreinterested in getting the harvests out to the people than inthe accuracy of production records. (White, 1973)described a similar experiment on the Niger floodplainsnear Lokoja. By constructing earth weirs across exitstreams from a swamp/lagoon system to increase thevolume of water, he recorded a harvest of 188 kg/ha fromunfed ponds. This figure was estimated to be double thenormal yield in previous years.

From the above review of available information onthe practice and prospects of floodplain pisci culture onthe Niger-Benue system, it should be clear that bothseasonal and perennial culture practices can beundertaken. Despite the fact that ponds are readilyavailable and water delivered naturally, there areattendant constraints in their utilization. It is not possibleto exercise effective control over the fish species whichwill pass into the culture media during the flood. Evenwith pre-culture cropping involving local pool-fisherymethods which spare neither adult nor fry, undesirablespecies especially ubiquitous tilapias and Hepsetus odoe,cannot be eliminated as experience in artificial pondfarms have shown (Sivalingam,1972).

Other constraints such as ownership/tenementproblems as well as institutional and allocative conflictsin the use of the fadama lakes may be easier to contain bynot only demonstrating the profitability of the proposalsbut also getting the local floodplain farmers and fishermeninvolved.

Because of the water supply characteristics, perennialculture can only be meaningfully undertaken in lakes,lagoons etc. Which meet most of the followingrequirements:

C Location on the outer limit of the floodplainC Maintenance of a desired minimal water level all the

year roundC In the drier areas, a considerable proportion of the

water supply (ca. 50%) should be derived from thecatchment area (as distinct from the river channel) inorder to ensure the maintenance of reasonably goodwater level through most of the year

C Channels connecting them to the main river shouldbe narrow and reasonably shallow. Those whichbecome functional only at the flood peaks because ofhigher location of the ponds are the best since theycan easily be cut off with earth dams

Similarly, swamps in shallow depressions withminimally suitable level at dry season can be put undersemi-culture to increase their yield. As for lakes andponds, the volume of water in them could be increased asdesired by constructing earth dams across connectingchannels. This procedure will no doubt improve the valueof traditional swamp fisheries on the floodplains. To

minimize the problem of eutrophication in adjacentfadama ponds found unsuitable for culture, fertilization ofculture ponds should be carefully controlled.

CONCLUSION

The interactions between the proposed fish cultureand existing uses of floodplain indicate the need todevelop overall and integrated management strategies inorder to optimize the exploitation of water resources. In acountry where animal protein is an expensive commoditysustainable culture fisheries management is inevitable. Itis suggested that these management measures shouldinclude:

C The sitting of agro-industrial complexes in such away that most of their water requirements can be metfrom the river.

C Pollution and eutrophication problems emanatingfrom industrial effluents, application of fertilizers andinsecticides in crop husbandry, are to be minimizedby the provision of a suitable drainage system for thefarms and industrial establishments. This may result,in some cases, in the loss of water from thecatchment to the natural pond farms. On the long run,however, the latter would be better off, provided thatthey can be refilled partly from the remainingcatchment and partly from the river floodwater.

C Filling of natural culture ponds: provision should bemade against the shortening of the life of cultureponds resulting from erosion from arable crop fields.Appropriate ridge orientation procedures and theprovision of additional cheap drainage channels,where necessary, would help to solve the problem toa large extent.

C Reduction of effects on capture fisheries: this can beachieved by excluding from culture purposes thelarger lagoons in which traditional dry season “poolfishery” is developing into a major annual event inthe life of the local people. Also, as shown above,emphasis on the utilization of larger culture ponds onseasonal basis would facilitate pre-culture poolfishery harvest from most of them, even if earlierthan normal, before fry/fingerlings are stocked.

C Since multipurpose dams are currently a sine qua nonin the maximal integrated exploitation of floodplainresources, management procedures to offset theireffects on all sectors of fisheries activities should beapplied. The provision of fish ladders in dams,strategically timed release of reservoir water and/orcanalization of the latter to desiccated floodplainlakes and ponds are some of the measures to meetthis exigency.

C To ensure the successful implementation,Government and voluntary organizations should


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sponsor research on fish culture in floodplain naturalwaters.

REFERENCES

Anonymous, 1972. Fisheries Report to the NationalAgricultural Development Seminar,1971 (Revised).

Awachie, J.B.E., 1968. Fish culture trials with naturalstock and ponds on the lower Niger floodplainnear Atani. Umudike: Report of the FisheriesInvestigation Unit (unpublished).

Awachie, J.B.E., 1969. A report on fish production trialsin kraals in selected rivers and lakes of EasternNigeria. Umudike: Report of the FisheriesInvestigation Unit.

Awachie, J.B.E., 1973. On conservation and managementof inland water resources of Nigeria. I. Natural lakesand ponds with special reference to their utilisationfor fisheries development. 1st Symposium onenvironmental resource management in Nigeria.University of Ife Press, Ile-Ife, Nigeria.

Eweka, J.A., 1973. Proceedings of the Nationalagricultural development seminar, 1971. CaxtonPress, Ibadan, Nigeria.

Ezeri, G.N., O.J. Olaoye and A.O. Agbon, 2009. FishFingerlings Production and Management.Aquacultural Media Resources and extension Center,University of Abeokuta, pp: 36.

FAO, 1966. Agricultural Development in Nigeria1965-1980. Rome, FAO.

Food and Agricultural Organisation (FAO), 2006. Yearbook of Fishery statistics-Summary Table. Retrievedfrom: www.fao.org/fi/statist.asp.

Hayward, L.A.W., 1961. Observation on the quality andlosses of dried fish from Lake Chad. West AfricanStored Products Research Unit, Lagos.

Holden, M.J. and J. Green, 1960. The hydrology andplankton of the River Sokoto. J. Anim. Ecol., 29:65-84.

Mann, M.J., 1962. Fish Production and Marketing fromthe Nigerian Shores of Lake Chad, 1960-1961.Federal Fisheries Service, Lagos.

Mutter, N.E.S., 1972a. Report of the Benue ValleyAppraisal Mission. Overseas DevelopmentAdministration, U.K., PROP/7/72.

Mutter, N.E.S., 1972b. Niger Valley Survey AppraisalMission September-December, 1971: Final Report.Overseas Development Administration, U.K.,PROP/6/72.

Mutter, N.E.S., 1973. Report of the Lower Niger SurveyAppraisal Mission. Overseas DevelopmentAdministration, U.K., PROP/14/73.

Olayide, S.O., 1966: A Quantitative Analysis of FoodRequirements, Supplies and Demands in Nigeria.Federal Department of Agriculture, Lagos.

Phelines, R.F., M. Coke and S.M. Nicol, 1973. Somebiological consequences of the damming of thePongola River. Proceeding 11th Congress on LargeDams - International Commission on Large Dams,pp: 75-90 (in French).

Pillay, T.V.R., 1962. Possibilities of fish culture inlagoons. Report to the Government of Ghana. RomeAmer. Assn. Adv. Sci., FAO, Report No. 1581.

Pillay, T.V.R., 1968. Estuarine Fisheries of West Africa.,Special Publication, Estuaries, pp: 639-646.

Sivalingam, S., 1972. Fish Culture Possibilities AroundLagos Lagoon and Results of Recent Trials. FederalFisheries Occasional Paper, No. 13. FederalDepartment of Fisheries, Lagos.

Welcomme, R.L., 1971. A description of certainindigenous fishing methods from Southern Dahomey.Afr. J. Trop. Hydrobiol. Fish., 1: 129-140.

Welcomme, R.L., 1974. The fisheries ecology of Africanfloodplains. In Report of the Consultation onfisheries problems in the Sahelian zone. CIFA Occas.Pap., 4: 40-81.

White, E., 1973. Zambia's kafue hydroelectric schemeand its biological problems. Geophys. Monogr. Ser.,17: 620-628.

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