Fish Hatchery Management, Fish hatchery requirements.docx

*Hatchery
*Purpose of Hatchery
*Importance of Fish Hatchery
*Hatchery Requirements
*Fish Hatchery Management: Steps to be taken
1. Control of Predatory and weed Fishes
2. Fish toxicants control
3. Aquatic insects and their control
4. Weeds control
5. Algal bloom control
6. Fertilizing the Fish Ponds
7. Natural food for fish
8. Supplementary food
9. Stocking rate

1. Fish Hatchery Management
Hatchery:
“A facility where eggs are hatched under artificial conditions.” (OR)
“A place for artificial breeding, hatching, and rearing through the early life stages of animals”
Explanation
A fish hatchery is a facility designed to raise fish. It provides an optimum environment for fish eggs to
develop and hatch by maintaining proper water temperature and oxygen levels, and providing adequate
food supplies and safety from predators. A hatchery works to raise baby fish and prepare them for
release in another environment for various reasons, as well as for food.
A hatchery is a mix of a laboratory and a farm, where fish and shellfish are spawned, then hatched and
cared for. They remain at the hatchery until they are large enough to be transferred to a fish or shellfish
farm or released into the wild as part of a stock enhancement program.
Species: Some species that are commonly raised in hatcheries include Pacific oyster, shrimp, salmon,
tilapia and scallops.
There are two production methods for fishes:
i) Capture ii) Culture
Purpose of Hatchery
There are some important purposes of hatchery system:
1. It is used for conservative purposes i.e. when a species become rare or endangered then this method
is used to breed that specie and increase their number.
2. May be for economic reasons like other countries export them at high cost.
3. One of the main and important purposes is for food purpose.
4. It improves genetic quality i.e. we provide some important conditions that sometimes are not
available in their natural habitats.
5. We reproduce them in out of season whenever we need them.

2. Importance of Fish hatchery
Fish hatchery management is efficient tool in intensive fish culture. The vital requirements of fish
hatchery are hatchery construction, concrete tank constructions, nursery, rearing and production ponds,
fish hatchery seed, hormone in fish spawning, hypophysation are basic elements in effective hatchery
management.
Hatcheries provide the seed for aquaculture and some commercial fisheries. All types of fish and
shellfish begin life in tanks in a hatchery. Commercial fish and shellfish farms require a steady,
predictable source of juveniles from hatcheries in order to stay in operation and provide a consistent
product.
Hatchery Requirements
There are few important factors or requirements of hatchery system which are given below:
1. Water quality:
Water quality determines to a great extent the success or failure of fish culture. Water quality should be
suitable for hatching fishes. Oxygen concentration should be near 100 percent in the incoming water
supply to a hatchery.
2. Temperature
Hatching eggs may be warmed to a temperature of 25° to 30°C prior to setting.
3. Salinity
The salinity rate where best results are found is at 12PPT.
4. Acidity
Some fishes becomes cultures in acidic pH i.e. Haddock hatched at 6.17- 6.82 pH. While whitefish
hatched at 5-6 pH.
5. Basicity
Guppies and swordtails hatched in alkaline pH i.e. at 7.0 – 8.5 pH.
6. Turbidity
“Turbidity” is the term associated with the presence of suspended solids. Analytically, turbidity refers to
the penetration of light through water. Abundant suspended particles can make it more difficult for fish
to find food or avoid predation.

3. Fish Hatchery Management
Steps to be taken:
1. Control of predatory and weed fishes
Predatory Fishes
Fishes which predate the spawn, fry and fingerling of cultured fishes.
They get into cultured ponds through water or seeds.
They breed easily in confined water little earlier than carps and therefore their size will be bigger
than the size of the carps.
They compete for food, space and DO and result in poor growth of carps.
Common predatory fishes are:
Channa spp., Clarias batraches, Heteropneustes fossailis, Pangsius, Mystus sp. Ompok spp., Wallage attu
and Glossogobius giuris etc.
Weed Fishes
These are uneconomical, small sized, naturally occuring or introduced accidentally in ponds
along with fish seeds.
They compete for food, space and dissolved oxygen.
They have high fecundity and breed well before major carps breed.
Many of them breed throughout the year.
Therefore, fish seeds from wild contain seeds of weed fishes.
Common weed fishes are:
Puntius sp., Oxygaster sp., Ambassis sp., Amblypharyngodon mala. Colisa sp., Rasbora sp., Aplocheilus
sp., Laubuca sp., Esomus danricus, etc.
Control measures
1. Repeated netting:
Repeated netting is suitable for only those ponds having no other fishes except carps.
It is not possible catch predatory and weed fishes simply by netting.
Remaining fishes will breed and have sizable population in the pond.
2. Dewatering the pond is the best method.
Dewater the pond, catch all the fish and allow the pond bottom to dry till the bottom soil cracks.
Summer is the best time for this.

4. 3. Using chemicals.
Bleaching powder with 30% chlorine content, when applied at 25-30 ppm, kills all varieties of fishes,
including catfishes, murrels, weed fishes and carps.
2. Fish toxicants control
Chemicals which are toxic for fishes are termed as fish toxicants.
These chemicals should be removed from that area where ponds are established.
Water should not be polluted.
Plant derivatives like Rotenone is alkaloid toxin which stuns fish by impairing their oxygen
consumption.
Chlorinated hydrocarbons like DDT and chlordane, endrin should be removed.
3. Aquatic insects and their control
Insects usually found in large numbers in ponds over the greater part of the year, especially
during and after rains.
They injure the spawn and some of them prey upon spawn.
Aquatic insects and their larvae compete for food with the young fish.
They cause large-scale destruction of hatchlings in nurseries.
Hence, the insects should be eradicated prior to stocking to ensure maximum survival of the
spawn.
Common aquatic insects found in nursery ponds are Notonecta, Ranatra, Cybister, Lethoceros,
Nepa, Hydrometra and Belostoma are highly destructive to the carp seed.
Control measures: Before hatching, the ponds should be cleaned from aquatic insects. We minimize
them through oil sprays like kerosene oil or diesel. The oil sprays spread over the water surface which
blocks the respiration for insects and as a result they die. Then after many days of oil sprays fishes are
stocked in the pond.
4. Weeds control
Aquatic weeds are plants that grow in the pond where they are not wanted.
Weeds uptake the essential nutrients and thus suppresses the growth and development of
plankton in the pond.
They also affect the water quality by stagnating water volumes and leading to anoxic and foul
conditions.
Some common aquatic weeds include Potamogeton, Eichhornia, Phragmites, Ceratophyllum.
We should control the weeds by using the weedicides like Naphathelene acetic acid, Atrazine for
removing unwanted weeds.

5. 5. Algal bloom control
Algal bloom: “The rapid increase of algae in water”
Algal blooms cover the surface of water bodies and thus limit the reaching of sunlight to the bottom of
the pond.
Control measures: Chemicals used for controlling the algal blooms are: 1) Simazine 2) Diuron
6. Fertilizing the fish ponds
Fertilizers are natural or synthetic substances that are used in ponds to increase the production of the
natural food organisms to be eaten by the fish. These organisms include phytoplankton,
zooplankton and insects.
Fertilizers used in ponds stimulate the growth of microscopic plants called algae or plankton. As primary
elements of the food web, algae are eaten by microscopic animals called zooplankton and insects are
eaten by fishes.
7. Natural food for fish in pond
Natural food is found naturally in the pond. It may include detritus, bacteria, plankton, worms, insects,
snails, aquatic plants and fish. Their abundance greatly depends on water quality.
It is to be ensured that there is a good supply of natural food for fishes. Phytoplankton organisms are
the easiest to produce using a good fertilization program. Zooplankton will then develop rapidly in the
presence of algae to graze upon.
8. Supplementary food
Supplementary feeds are regularly distributed to the fish in the pond. They usually consist of cheap
materials locally available such as terrestrial plants, kitchen wastes or agricultural by-products.
9. Stocking rate
It refers to the quantity of fry or fingerling per unit of water area.
Good growth of fish depends upon the right number of fish cultured in the pond. The stocking
rate depends on the volume of the water and on the oxygen balance of the pond rather than
the size of the pond.
The desirable stocking rate is 7000-9000 fishes per hectare.