lake fisheries

8/7/2019 Lake Fisheries

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Lake fisheriesLake fisheries

Main fisheries of the lake:Main fisheries of the lake:

GambusiaGambusia

PuntiusPuntius Silver carpSilver carp

Other noticeable fisheries is that ofOther noticeable fisheries is that ofCommon carp in the littoral zonesCommon carp in the littoral zones


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Keystone disturbing elements inKeystone disturbing elements in

the lakethe lakeGambusiaGambusia-- a larvicidal fish is one of thea larvicidal fish is one of the

main causes of disturbance in the lakemain causes of disturbance in the lakeecosystemecosystem-- increasing the nutrientincreasing the nutrient

concentration; increasing phytoplanktonconcentration; increasing phytoplanktonpopulation; reducing transparency;population; reducing transparency;disturbing the population of useful fishes indisturbing the population of useful fishes inthe lake; grazing on zooplankters etc.the lake; grazing on zooplankters etc.

The removal of Gambusia population isThe removal of Gambusia population istherefore very important.therefore very important.


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PuntiusPuntius spp.spp.

Puntius has emerged as a dominant fishery of the lake during thePuntius has emerged as a dominant fishery of the lake during thefishing operations carried out in the lake in the past monthsfishing operations carried out in the lake in the past months

Mortality ofMortality ofPuntiusPuntius also occurs in the lake during adverse ecologicalalso occurs in the lake during adverse ecologicalconditions.conditions.

PuntiusPuntius grazes on zooplankton. Hence it will reduce the pupulationgrazes on zooplankton. Hence it will reduce the pupulation

of zooplanton which graze on phytoplanktonof zooplanton which graze on phytoplankton It does not grow to a large size and does not have sport or foodIt does not grow to a large size and does not have sport or food

valuevalue

It breeds in the lake and its population may become uncontrollableIt breeds in the lake and its population may become uncontrollableafter aeration.after aeration.

Like Gambusia it also affects the community structure ofLike Gambusia it also affects the community structure of

zooplanktonzooplankton It will compete with Mahseer for food after the stocking of the latter.It will compete with Mahseer for food after the stocking of the latter.

The removal of the excessive population ofThe removal of the excessive population ofPuntiusPuntius is thereforeis thereforeessential.essential.


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Common carp fisheriesCommon carp fisheries Common carp fisheries existsCommon carp fisheries exists

in the lake especially in thein the lake especially in the

littoral regionslittoral regions

The fish breeds in the lake.The fish breeds in the lake.

It is therefore difficult toIt is therefore difficult to

maintain its controlledmaintain its controlledpopulation in the lakepopulation in the lake

After aeration its fishery willAfter aeration its fishery will

also get established in thealso get established in the

profundal region.profundal region.

The uncontrolled population ofThe uncontrolled population ofcommon carp will not allow thecommon carp will not allow the

development ofdevelopment of

environmentally importantenvironmentally important

fishery of mahseerfishery of mahseer..


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Why removal of unwanted fishes isWhy removal of unwanted fishes is

importantimportant Adversely affect the ecosystem of the lakeAdversely affect the ecosystem of the lake

The uncontrolled population increases theThe uncontrolled population increases the

concentration of the nutrientsconcentration of the nutrients

Cause imbalanced populations of phyto andCause imbalanced populations of phyto and

zooplanktonzooplankton

Alter the community structure of the planktonAlter the community structure of the plankton

communities like increased population of bluecommunities like increased population of bluegreen algae, disappearance ofgreen algae, disappearance ofDaphniaDaphnia etc.etc.

Increase concentration of nutrientsIncrease concentration of nutrients


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Development of environment friendly fisheriesDevelopment of environment friendly fisheries

Fishes which do not affect the ecosystem of the lakeFishes which do not affect the ecosystem of the lake

Fishes which can help in reversing the eutrophication ofFishes which can help in reversing the eutrophication ofthe lakethe lake

Fishes which can help in maintaining a proper balance ofF

ishes which can help in maintaining a proper balance ofphyto and zooplankton populations in the lakephyto and zooplankton populations in the lake

Fishes whose controlled population can be maintained inFishes whose controlled population can be maintained inthe lakethe lake

Endemic fisheries of the lakeEndemic fisheries of the lake

Which are of food value to the people and provide sportWhich are of food value to the people and provide sportto the peopleto the people


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Silver carp fisheriesSilver carp fisheries

Silver carp was stocked in the lake for theSilver carp was stocked in the lake for thecontrol of phytoplanktoncontrol of phytoplankton

It has well established in the lake withIt has well established in the lake withindividual fish weight reaching up to 10individual fish weight reaching up to 10--1212kgkg

There is need for selective fishing of silverThere is need for selective fishing of silver

carp; large sized fishes can be removedcarp; large sized fishes can be removed Stocking of fresh stock of silver carpStocking of fresh stock of silver carp

should be continued.should be continued.


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Development of mahseer fisheryDevelopment of mahseer fishery

It is the endemic fishery of lakeIt is the endemic fishery of lakeNainitalNainital

Due to pollution the mahseerDue to pollution the mahseerfishery has almost vanished fromfishery has almost vanished fromthe lakethe lake

It is an omnivorous fish and hasIt is an omnivorous fish and hasgreat food valuegreat food value

It is also the world renowned sportIt is also the world renowned sportfish attracting the people from farfish attracting the people from farand wide for sport fishing.and wide for sport fishing.

The successful establishment ofThe successful establishment ofmahseer fishery is possible aftermahseer fishery is possible afteraeration of the lake.aeration of the lake.

The technology for breeding andThe technology for breeding andlarval rearing has been developedlarval rearing has been developed

which will facilitate its stocking inwhich will facilitate its stocking inthe lake every year.the lake every year.

Development of mahseer fisheryDevelopment of mahseer fisherywill help in maintaining a stablewill help in maintaining a stablefood chain the lakefood chain the lake


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Benefit of developing theBenefit of developing the

environment friendly fisheryenvironment friendly fishery Development of balanced fishery of silver carpDevelopment of balanced fishery of silver carp

and golden mahseer will help in maintainingand golden mahseer will help in maintainingbalanced population of phytoplankton andbalanced population of phytoplankton andzooplanktonzooplankton

It will improve the watery quality of the lakeIt will improve the watery quality of the lake Mahseer fishery in the transparent waters ofMahseer fishery in the transparent waters of

Nainital after aeration will increase the touristNainital after aeration will increase the touristattraction of the lake.attraction of the lake.

Both aeration and biomanipulation will reverseBoth aeration and biomanipulation will reversethe eutrophication of the lake and bring the lakethe eutrophication of the lake and bring the laketo its old glory.to its old glory.


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Fishing guidelinesFishing guidelines

The detailed guidelines for fishing in lakeThe detailed guidelines for fishing in lakeare being developed taking intoare being developed taking intoconsideration:consideration:

The present fish faunaThe present fish fauna

Stocking of fishes to be doneStocking of fishes to be done

Long term perspective of fisheriesLong term perspective of fisheries

development in the lake visdevelopment in the lake vis----vis thevis therestoration of lake ecosystem throughrestoration of lake ecosystem throughbiomanipulationbiomanipulation


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Management StrategiesManagement Strategies

PartPart


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Management OptioonsManagement Optioons AA IntroductionIntroduction ofof newnew speciesspecies toto exploitexploit underunder--utilizedutilized partsparts ofof thethe foodfood chainchain

oror habitathabitat notnot colonizedcolonized byby thethe residentresident faunafauna.. StockingStocking naturalnatural waterswaters toto improveimprove recruitment,recruitment, biasbias fishfish assemblageassemblage

structurestructure toto favoredfavored speciesspecies oror maintainmaintain productiveproductive speciesspecies thatthat wouldwould notnotbreedbreed naturallynaturally inin thethe systemsystem..

FertilizationFertilization toto raiseraise thethe generalgeneral levellevel ofof productivityproductivity andand hencehence growthgrowth ofof thethefishfish..

EngineeringEngineering ofof thethe environmentenvironment toto improveimprove levelslevels ofof reproduction,reproduction, shelter,shelter,

foodfood resourcesresources andand vitalvital habitathabitat;; EliminationElimination ofof unwantedunwanted speciesspecies thatthat eithereither competecompete withwith oror predatepredate uponupon

targettarget speciesspecies..

ConstitutingConstituting anan artificialartificial faunafauna ofof selectedselected speciesspecies toto increaseincrease thethe degreedegree ofofcontrolcontrol andand thethe yieldyield fromfrom thethe systemsystem..

ModificationModification ofof waterwater bodiesbodies toto cutcut offoff baysbays andand armsarms toto serveserve forfor extensiveextensiveandand intensiveintensive fishfish pondsponds toto increaseincrease controlcontrol andand nutrientnutrient flowsflows;;

IntroductionIntroduction ofof cagecage cultureculture andand parallelparallel intensificationintensification ofof efforteffort ofof thethe capturecapturefisheryfishery..

AquacultureAquaculture throughthrough managementmanagement ofof thethe wholewhole systemsystem asas anan intensiveintensive fishfishpondpond..

GeneticGenetic modificationmodification ofof culturedcultured speciesspecies toto increaseincrease growth,growth, production,production,diseasedisease resistanceresistance andand thermalthermal tolerancetolerance ofof thethe stockedstocked oror culturedcultured materialmaterial..

AndAnd soso onon


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Topographical features of drainage & basinTopographical features of drainage & basin


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Number of River systemsNumber of River systems--

The NorthernThe Northern // HimalayanHimalayan river systems (Ganga, Brahmaputra & Indus)river systems (Ganga, Brahmaputra & Indus)

The SouthernThe Southern // PeninsularPeninsularriver systems (PECRS & PWCRS)river systems (PECRS & PWCRS)

lake fisheries

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