Nursery pond management of Fishes

Nursery Pond management of Fish or shrimp

1. NURSERY POND MANAGEMENT
By
Dr. K. NarasimhaMurty

2. Introduction
Different types of ponds are required for the culture
They are nursery, rearing and production or stocking ponds
According to Alikunhi, under Indian conditions, 4 hec., fish farm
should have the following ratio
Nursery pond: 0.2 hec.
Rearing pond: 0.8 hac.
Stocking pond: 3.0 hac

3. Nursery Ponds (NP)
These are smallest of the fish ponds measures about 0.02-0.06 hact.,
and 1 met in depth.
These are meant for nursing the hatchlings/spawn (5-6 mm) for a
period of 15 to 30 days until they become fry (2.5-3.0 cm).
In practice about 10 million spawn per hect., are stocked in NP.
The NPs may be earthernor constructed with brick and cement.

4. RearingPonds(RP)
TheseareslightlylargerthantheNPs.
Usuallymeasureabout0.08-0.1hact.,
DepthoftheRPs1.0-1.5m.
InRPs,thefryaregrownforabout2to3monthsuntilthey
become(fingerlings8-12cm).

5. StockingPonds(SP)
SPsarealsocalledProductionpondsorGrow-outponds.
Thesearethelargestamongotherpondsinafarm.
SizeofSPs0.4-40hact.,ormorebuttheidealsizeforefficient
managementis2to4hact.,
Depthofwaterintheseponds1.5-3m.
Intheseponds,thefingerlingsandadvancedfingerlingsorjuveniles
arereareduptomarketablesizeforabout6monthstooneyear.
Theeconomicsizeofthepondsdependsontheecologicalconditions
oftheareaandthetypeoffishculture.

6. StockingPonds(SP)

7. NurseryPondManagement
Thenurserypondmanagementincludespre-stocking,stockingand
poststockingmanagement.
A.PRE-STOCKINGMANAGEMENT
i)Dewateringanddrying
ii)Desilting
iii)Controlofpredatoryandweedfishes
iv)ControlofAquaticweeds
v)Liming
vi)Watering
vii)FertilizationorManuring
viii)ControlofAlgalblooms
ix)ControlofAquaticinsects
x)Waterquality

8. i)Dewateringanddrying
Firstwaterisremovedfromthepondsandexposedforsun
drying.
Dryingofpondsinsummerhelpsinthemineralizationofsoil,
removaloforganicdetritus,andautomicdestructionof
pathogens,aquaticweeds,predatoryandunwantedfishes.
ii)Desilting
Thesiltwithrichhumusorexcessorganicmatteratthe
bottomisremovedandthiscanbeusedtofillthesidesandfor
strengtheningthebunds.

9. iii)ControlofpredatoryandweedFishes
ThecommonpredatoryfishesareChannaspp.,Wallagoattu,
Clariasbatrachusetc.,
Thesecauseheavymortalityofspawnastheyfeedonspawn.
ThecommonweedfishesarePuntius,Bariliusetc.,
Theweedfishesarenotpredatorybuttheycompleteforfood
andspacewiththeculturefish.
Theymustbeeradicatedfromthenurserypondeitherby
nettingorbypoisoning.

10. Clarias batrachus
Puntius

11. TreatmentofPredatoryandWeedfishes
Chlorinatedhydrocarbonsandorganophosphates
Derrisrootpowder :5ppm
Mahuaoilcake :200ppm
Teaseedcake :75-100ppm
Chlorinatedhydrocarbons(Aldrin):0.2ppm
Dieldrin :0.01ppm
Endrin :0.001ppm
Organophosphates,nuvan(DDVP) :2-20ppm

12. iv) Control of Aquatic Weeds
Aquatic weeds affect the fish culture by
Limiting the space for movement
Competing with phytoplankton by absorbing nutrients
Causing imbalance in the DO concentration
Causing siltation
Hampering netting operations and harboring unwanted
fishes, insects and molluscs

13. Aquatic weeds
Algal weeds : Spirogyra, Chara
Floating weeds : Eichhornia, Lemna andPistia
Emergent :Nymphaea, Typha
Submerged : Vallisneria, Hydrilla andUtricularia
Marginal : Marsilia, Ipomoea

14. Algal weeds
Spirogyra

15. Ipomoea
VallisneriaNymphaeaPistia

17. Control of Aquatic Weeds
Use mechanical, chemical and biological methods
Mechanicalmethodincludescollectionanddisposalofthe
weedsbycutting,dragging,ploughingetc.,
Chemicalmethodinvolvessprayingofchemicalssuchas
Simazine :5kg/ha
Ammonia :15ppm
80%2-4D :5-7kg/ha
(2-4dichlorophenoxyaceticacid)forfloatingweeds
Emergentweeds:Dichlorophenyl:10kg/haor
fenate(2,3,6trichlorophenylaceticacid)

19. Submerged weeds
Ammonia : 15 ppm
Simazine : 3-5 ppm
Fenate : 10 kg/ha
Marginal weeds
Dichloropheynl : 10 kg/ha
Diquats : 1 kg/hac

20. Biological methods
Introducing the Grass carp and common carp that feed on
most of the weeds except Salyinaand Eichhornia.
v) Liming
This is the first step in the fertilization of a nursery pond.
Liming is most essential to maintain the pH of water.
Range of 7.5-8.5
It helps to eradicate the harmful bacteria and fish parasites.
Common carp, Cyprinus carpio

22. pH of soilSoil conditionDose of lime;
Kg/ha
4.0-4.5 Highly acidic 1000
4.5-5.5 Medium 700
5.5-6.5 Slightly 500
6.5-7.5 Near neutral 200

23. vi) Watering
To avoid the entry of exogenous fish into the pond,
Eg. Unwanted eggs, young or adult stages
vii) Fertilization
Fertilization has to be done after filling the pond with water.
Themainaimoffertilizationofwateristheproductionof
adequateofquantitiesofplankton,naturalfoodofcarp
spawn.

24. Fertilizers used in ponds are of two types
1. Organic manures
2. Inorganic manures
Super phosphate: 250 kg/ha
DAP : 80-100 kg/ha
GOC : 250 kg/ha

25. viii) Control of algal blooms
Algalbloomsareinvariablycausedbyunicellularand
filamentousalgaewhichimpactgreen,reddish-brownand
bluish-greencolourationtothewater.
Eg.Euglena,Volvax,Prdidinium,BGA
Controlledbythe1ppmcoppersulphate,05ppmsimazine

26. ix) Control of aquatic insects
Afterwateringandfertilization,predatoryaquaticinsects
maysometimesdevelopenormously.
HemipteraandColeoptera
Waterstrider,backswimmers,waterscorpions
Divingbbeetles(Cybister);whirligigbeetle(Dineutes)
Theoilemulsionwith60kgofoiland20kgsoapare
suffecienttotreat1hacofwater.
Dieldrin0.5ppm,benzenehexachloride0.1ppm

27. Orders you may encounter Ephemeroptera (mayflies)
Eggs –larva –subimage -adult
Larva –elongate, 3 filaments (tail), can have 2
Lamellate gills along abdomen
Well developed legs
Perpendicular wings on adults

28. Plecoptera (stoneflies)
•Same life cycle as mayflies
•Have 2 filaments
•No lamellate gills along abdomen
•Some have filamentous gills
•Adult wings are flat
•Mostly shredders and grazers

29. Odonata (dragonflies, damselflies)
•Eggs –larva –teneral adult -adult
•Predacious
•No external gills
•Longer body on damselflies (wings up)
•Dragonflies (wings down)

30. Diptera (midges, mosquitoes, gnats, flies)
•Elongate body
•Segmented body
•Most species rich order (includes Chironomidae)
•Adults have one pair of wings
•Very diverse morphology

31. Hemiptera (true bugs)
•Egg –nymph larva –adult
•Predacious “beak”
•Wing pads
•If wings develop they fold over each
other

32. Coleoptera (beetles)
•Egg –larva –pupa –adult
•Larva very different from adult
•Adults –have hard case on body that does not
overlap
•Adults have chewing mouthparts
•Larva –undeveloped eyes, sometimes have tusks

33. Megaloptera (alder flies, dobsonflies)
•Mouth has large, chewing pinchers (predacious)
•Abdomen has strand-like appendages extending from each side
•Three pairs of segmented legs on middle section of body
with tiny pinchers at the end of each
•Each segment contains filaments for respiration
•Abdomen ends with two elongated appendages or prolegs

34. x) Water quality
Brown colour of water indicates rich zooplankton.
Greenorbluecolourindicatesdominaceofalgaeinthe
plankton.
Rangeofsomeofthechemicalparameters
DO :5–8ppm
pH :7.5–8.5
CO
2 :<15ppm
NH
3 :<0.5ppm
PO
4 :1.0-20ppm
NO
3 :1ppm

35. B. Stocking
Nursery ponds generally stocked at the rate of 5-6 million
spawn/ha.
C. Post-stocking Management
Feeding:
After stocking, the spawn start feeding voraciously on the
plankton.
Survivalandgrowthofspawnareinfluencedmostlyby
thequantityandqualityoffoodavailableinthepond.
Artificialfoodisnecessary.
Thefeedingscheduleisasfollows
2-5days -doubletheinitialbodyweightofthespawnstocked
6-10 days -thrice the initial body weight of spawn stocked
11-15 days -four times the initial body weight of the spawn stocked

36. D)Harvesting of fry
In15daysofnurseryrearing,thespawngrowstoa
sizeof20-25mmfry.
Atthisstage,thefrycouldbeharvestedand
transferredtorearingponds.
Supplementaryfeedingshouldbestoppedadaybefore
harvesting.
Using1/16”meshdragnet.
Survivalratewouldbe60-80%

37. Thank you