GODFREY OKOYE UNIVERSITY FISH FARM
Commercial breeding of African Catfish involves reproduction of young catfish (fry) using expensive synthetic ovulating hormones such as ovaprim, gornopro etc. the production of commercial catfish by either breeding or stocking of fry or juveniles into rearing environment that can provide optimum and rapid growth to allow harvest after a short time depending on your feeding plan.
The greatest advantage of commercial farming of African catfish is the production of young fry which are reared to table size. The difficulties of getting consistent disease free resistant strain which will grow fast into juvenile/table sized catfish is paramount and dependent on achieving a success in disease control, juvenile selection and feeding.
This propagation of African catfish involves expertise as it is a dynamic field on its own and involves accurate labeling and conducive environment for the eggs to hatch when their is accurate water pH, aerator to supply air, limestone to efficiently harden the water to induce egg hatchery, quality brood-stocks for the propagation and finally create adequate time to take care of the fry’s as they hatch.
The key to successful fish fertilization is the avoidance of bacterial contamination which can lead to infestation and loss, therefore the Propagation of catfish fry’s need so many technical and expertise experience starting from identification of sexes
- Identification of matured brood-stocks and sexes:
Male and female African catfish can be easily recognized. The male has a distinct sexual papilla, elongated and located just behind the anus. This sexual papilla is usually red at the tip for sexually ready males. It is absent in females. A sexually ready female has a swollen, usually reddish genital opening. A view from the top also gives a female African catfish away since either side of the belly appears swollen.
- Prepare the female Catfish for injection :
Hypothetically, 8 -15% of the weight of a gravid female fish is the weight of the eggs.
A female catfish that therefore weighs 500grams has the weight of the egg to be 50 grams.
A gram of egg contains approximately 700 eggs.
Thus a gravid female African catfish with a weight of 500grams could boast of 35,000 eggs.
Thus, a broodstock of 2500gram weight can be injected with 2ml of synthetic hormone
The viability of the eggs depends on brood stock care and management.
HOW TO INJECT HORMONE TO A FEMALE BROODSTOCK
NOTE: cover the female catfish head with a wet towel before injecting the hormone in other to calm the fish down and prevent the fish from contact with visible light
Injection is most Preferred if the syringe points towards the head of the female catfish. After injection, separate the injected female catfish and allow the egg to mature for stripping for 12 hours.
- Get the sperm milt sac ready:
Get your matured male catfish of about 10 months and above, kill and extract the sperm milk sac
Remove the sperm milk sac, clean off the blood on it and store inside normal saline until the egg is stripped.
- Stripping of eggs:
This part is very delicate and sensitive when handling the injected female broodstocks. Carefully remove the female broodstock from the bowl to avoid falling out of matured eggs. This can be done by covering the head with moist towel to avoid the fish from seeing any visible light.
- Remove the sperm milk sac from the normal saline, cut it open and mix it with stripped eggs. Mix well for a minute, add water and mix thoroughly for 3 minute,
Note: once you add water to the egg already mixed with sperm milk sac, fertilization will commence.
- Add limestone to the incubator to make the water hard and pilot efficient hatching of the eggs.
- Spread your fertilized eggs into your prepared incubator with spawning sponge already immersed in water. The spawning sponge can be floating on the water surface or held with peg or anything depending on the arrangement of the incubator. This will allow the sponge from falling inside the incubator. Pour your eggs on the spawning sponge and allow the eggs to hatch after 25-36 hours
After 25 to 36 hours, remove the sponge and spawning net. By now the fry would have emerged from the hatched eggs and would have gone to the bottom of the net.
The un-hatched ones, now attached to the spawning sponge and spawning net are removed from the water since they would be attacked by fungi if left for too long. These fungi would inevitably attack the hatched eggs at the bottom of the net.
- 19 steps to efficient African catfish breeding _ The Fish Site.html
- Odedeyi, D.O. (2007). Survival and Growth of Hybrid (Female Clarias gariepinus (B) and Male
Heterobranchus longifilis (Val.) Fingerlings: Effect of Broodstock Sizes. American-Eurasian
Journal ofScientific Research 2 (1): 19-23, 2007.