Enhanced growth of Cage Cultured African catfish (Clarias gariepinus) through Polyculture with Nile tilapia (Oreocromis niloticus) in Chepkoilel fish ponds.

Abstract

The African catfish, (Clarias gariepinus) and the Nile tilapia, (Oreochromis niloticus) were cultured in polyculture and monoculture cages, (lm3) within a pond at Chepkoilel fish farm. A second control cage contained a monoculture of Oreochromis niloticus. The polyculture cage was stocked with forty- C gariepinus with a mean weight of 45.5 ± 4.08g and twenty 0. niloticus with a mean weight of 28.7 ± 2.05g. The cage for monoculture consisted of sixty - C. gariepinus with a mean weight 45.5 ± 4.08g. Fish were fed on a diet of 32% crude protein and growth monitored for 60 days. Mean weight of C. gariepinus were higher but not significant in polyculture (74.5 ± 7.2g) cage than in monoculture cage (66.4 ±5.06g) (t=-2.95, P=0.06). Net production of C gariepinus was also higher but not significantly higher in polyculture (0.029 ± 0.004kgs) cage than in monoculture cage (0.0209 ± 0001kgs) (t=-2.l8, p>0.05) whereas the food conversion efficiency and condition factor for C. gariepinus did not show any significant differences (t=-1.71, p>0.05). Growth rate was higher in polyculture (0.48± 0.001) than in monoculture (O.35± 0.001) cage and this was determined using the linear regression formula; Yt= a + bXt. Survival rate was 100% in both polyculture and monoculture cages, this was determined as Oreochromis niloticus was observed to feed very vigorously at all feeding periods which is thought to have stimulated C. gariepinus to higher feeding and growth rates, although this project is preliminary and needs improvement in terms of design, it shows that cage polyculture is likely to provide higher yield of C. gariepinus than monoculture.