2. Content
INTRODUCTIOUN
Data about fish seed
Selection of ponds for nurseries
Management for raising carp seed
Clearance of aquatic weeds
Eradication of unwanted fish (Predatory fish)
Eradication of unwanted of fishes
Mahua oil cake
Manuring of pond
Manuring procedure
Importance of organic manure
Liming
Oil-Soap Emulsion
Conclusion
3. INTRODUCTIOUN
Pre stocking management is one of the important method of entire three tire fish
farming system. Because, fish mortality is very high at the stage of spawn.. The
stocking density of nursery pond is 2 lacks/ha.
In Nursery pond fish nursed very well to prevent fish mortality.
4. Data about fish seed :
The tender spawn locally termed as “dimpona” start feeding after three days
of hatching.
Henceforth they need a congenial environment with enough food for growth
and survival.
The spawn of 5-8 mm sized are nursed in well prepared nurseries
Grown to fry of 25-30mm size in about 12- 15 days.
The weight of spawn is 0.0014gm & weight of fry is 0.5gm.
5. Selection of ponds for nurseries:
Seasonal pond, that dry up in summer are preferable ones.
As nurseries since seasonal exposure of the pond bottom to
direct sunlight help in improving pond condition.
Duck should not be allowed to enter nurseries because of their
predatory habits.
Size of Nursery pond:
Nursery pond should be small & rectangular in shape.
With an area of 0.02 to 0.04 ha (i.e. 3-6 kathas ) and a depth of
1 meter.
6. Management for raising carp seed :
Aiming at providing the delicate spawn enough space
for movement and sufficient food in the environment
free of pond-dwelling enemies.
Nurseries are specially prepared just before the
monsoon.
7. Clearance of aquatic weeds:
Weed infested nursery pond is detrimental to the
growth of spawns. The harmful effects of weeds are –
Limits the space for free movement of growing spawn.
Hampers netting operation.
Causes misbalance of dissolved oxygen content of
water.
Provides shelter for unwanted fish, mollusc, insects etc.
Hampers natural food production of fish by competing
with the phytoplankton by observing nutrients
8. Eradication of unwanted fish (Predatory fish):
Predatory fishes directly pray upon the young ones.
It competing with them for space and oxygen.
The commonly predatory fish species are-
1.Channasp
2. Mystus sp
3. Clarias batrachus
Eradication of unwanted fish (Weed fish):
Weed fishes compete with the cultural fishes for their demand of food.
They also compete for space and oxygen.
The common weed fishes are-
1.PuntiusPuntius
2 .Ambasiasp
3.Esomus daricus .etc
9. Eradication of unwanted of fishes:
Use of fish toxicants:
For complete removal of unwanted fishes in
perennial pond, fish toxicants may be use.
It should more be economically when water level
is low.
But in case of seasonal pond dry up generally
summer months, devoid some fishes, hence no
poisoning is required
10. Mahua oil cake:
The most used fish toxicants is mahua oil cake.
It containing 4-6% saponin.
Saponin is toxic for fish
It kills fishes at 200-250ppm, i.e. 2000- 2500kg/ha, within 4-6
hours.
The fishes thus killed are fit for human consumption.
The added advantages is that it also act as a fertilizer after its
poisoning effect.
11. Manuring of pond:
After seven days of mahua application the pond should be manure.
It should be manure with raw cow dung (RCD) @ 5000 kg/ha.
@ 10,000 kg/ha where mahua oil cake is not applied.
Pond should manure about 10- 15 days before the date of stocking
Phase Manuring :
Beside another method of fertilization also known as “phase Manuring”.
It is also known as “partial Manuring”.
It followed in be watered-pond for quick preparation
In this process after accumulation of rain water the following Manuring
procedure should be followed
12. Manuring procedure:
1st day 4500 kg RCD/ha
750 kg MOC/ha
360 kg SSP/ha
2nd day No Manuring, but the pond should be
Racked
3rd day 50% of the first dose
4th day Liming @200 kg/ha
5th day 25% of the first dose
6th day Eradication of aquatic insects by soap
oil emulsion
7th day Netting and remove the died insects
13. Importance of organic manure
• Organic manure is applied in the pond to increase the
production of natural fish food.
• Naturals food are zooplankton because, at this stage the
hatchlings voraciously feed on zooplankton.
• The day after eradication of aquatic insects, spawn may be
stocked.
14. Control of aquatic insects & enemies :
• Before releasing fish seed, the aquatic insects,
frogs and aquatic snake should eradicated
from from the nursery pond.
• It should be done by repeated netting.
• By this 75% of insects and other enemies may
be effectively removed.
• This operation is to be followed by spraying
soap-oil emulsion.
• Which will effectively kill rest of the insect
population by hampering their respiration.
15. Liming:
The pond which are acidic in nature are less productive than alkaline ponds. Lime is used to
bring to the pH to the desire level. In addition lime also has the following effects -
• increases pH
• acts as buffer and avoid fluctuations of pH.
• it’s toxic effect kills the parasite.
It hastens organic decomposition
Oil-Soap Emulsion :
• This emulsion can be prepared by mixing cheep detergent (18kg/ha ) in diesel oil or
kerosene oil
• During preparation some water is to be added to make a proper emulsion.
• The emulsion is applied at least 24 hours before releases of fish seed.
• On next day the dead insects should be removed by repeated drag netting.
• The water should be thoroughly stirred so as to remove the oily layer from the surface of
water.
• Now pond is ready to remove the fish seed.
16. Conclusion :
In nursery pond spawn converted to
fry in 10-12 days. So we use nursery
pond 3-4 times in a year for a
hatchery. So pre stocking
management of nursery pond has a
good importance in aquaculture.