WATER RELATED PROBLEMS IN FISH FARMING.

Water parameters play a vital role in fish farming,these parameters are directly related to the stocking density ,feed and feeding technique.Oxygen levels in the pond must be maintained at 4mg/litre. The concentration can be altered when the weather changes such as excessive high temperature,this reduces the solubility of oxygen in the pond.This results in suffocation of the fish in the pond,this results in high mortality. The dissolved oxygen level is usually depleted in cases of heavy algae bloom,this results from excess use of manure in the pond.The amount of feed given at any point in time also imparts the level of oxygen.when there is overfeeding or just after feeding of the fish and there are excess feed in the pond because there is an increase in demand of oxygen to digest the feed.Overcrowding in the pond due to overstocking also depletes the oxygen concentration. The fish show signs when the water parameters are altered or when there is a compromise due to pathogenic agent.The fish crowd near the water surface gasping for air,they reject feed,they dont respond to noise and their sputum remains undissolved on water surface. The water in the pond should be changed and replaced with fresh water,stop feeding at this period and stop fertilization of the pond.The oxygen level is corrected by aerating the pond using air pumps/aerators to increase oxygen level. Ammonia level( 0.05mg/litre) is also another important health indicator.The feed components are the key factors,when feed content are not properly metabolized,they give off high levels of ammonia in waste material,leading to contamination of pond due to accumulation of waste at the bottom of the pond.The pond could also have high levels of ammonia,if there is a contamination of ponds by sewage waste due to a leak from sewage pipes. The fish responds by reducing feed intake and also come to the surface for air.The ammonia level can be corrected by using more easily metabolized feed ;this can be achieved by using atovi premix in fish feed.This ensures proper metabolism of feed without any ammonia buildup,thus maintaining the regular level of ammonia.The atovi premix acts on the feed,fish and water in the pond(read more about atovi and fish in previous posts).In ponds where atovi feed is not used,the pond level must be reduced,it must be flushed and clean water is added to oxygenate pond. Foul smelling /odor in the pond this is usually as a result of feeding uncooked offal's to the fish,this is a major cause of pollution in fish pond. The uncooked offal s usually crowd/clog the water surface,depleting oxygen concentration ,giving off foul odor with resultant death of fish. The effect is reversed by removing left over offal s on water surface,flush pond and fill pond with fresh clean water.The use of uncooked offal's should be stopped and use compounded ration instead. Fish health is hinged on good water parameters,feed quality,quantity and frequency of feeding,hence much attention must be given to these factors.Observation and good management protocol are the keys for a successful fish farming venture.

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.