FINGERLING PRODUCTION.

Fingerling production in cat fish farming is an essential part of the farm operation because it is the seed needed for production.The Clarias gariepinus spp is the common cat fish reared in Nigeria because of its early maturity taste,and the fact that it has an accessory breathing organ hence can survive outside water for some hrs,this explains why its sold live in the open markets. The mature male and female brood stock are chosen and kept in separate tubs,one male can fertilize 10 females.The males are bigger and heavier than the females,weighing over 1kg is the ideal .The males must have well developed genitals that are reddish indicating maturity. The females to be used must be identified as good spawners,with a weight of 450-500g,and must be over 8months with dark golden green eggs. The females are usually injected with hormones,the eggs expressed and mixed with milt of the male catfish.The male catfish is killed to extract the milt while the female is returned to pond after eggs are expressed. There are various hormones used in stimulating ovulation in fish such as ova prim, human chorionic gonadotropin, crushed pituitary gland and a combination of motilium and suprefact. The materials needed for the spawning include; a glass trough or a bath tub with water inlet and outlet pipes, screen with stand, pumps,bowls and net covering to keep tank covered and dark.The method you intend to use will dictate materials you will put in place. METHOD; The female brood fish to be used are injected with hormone,and left for 10 hours in a tank with flowing water,after which the eggs are stripped and placed in a bowl and fertilized with sperm from milt sac.The testis are cut in quarters,placed in a cloth and squeezed ,so that the sperm is caught on the bowl of eggs and the mixture is gently stirred.The fertilized eggs are placed on the screen in the bath tub and hatching occurs in 24-30 hours. The eggs can also be spawned in bowls with air pumps,this continuous movement of the water facilitates rapid hatching of the eggs .The eggs start hatching after 24 hours,you observe the hatchlings swimming in the bowl,allow 12 more hours for other eggs to hatch,after which you discard the unhatched eggs. The hatchlings are transferred to nursery tank,but are not fed until the 3rd day when there is complete absorption of yolksac. The fry's are fed with artemia ,and growth is observed and monitored.The fry's are sorted every week until they are a month old,then select the fingerlings for sale or continue rearing and sell as juveniles.