Review Article
Sebastian S Mosha, Jeremiah
Abstract
Two experiments were conducted to assess the effect of organic and inorganic fertilizers on natural food composition and performance of African catfish (Clarias gariepinus) fry produced under artificial propagation. In both experiments chicken manure, di-ammonium phosphate and no fertilizer were used as treatments. The first experiment was conducted to determine the abundance and diversity of natural food produced in tanks fertilized with chicken manure and di-ammonium phosphate fertilizer. The second experiment was conducted to assess growth performance and survival of catfish fry produced in chicken manure and di-ammonium phosphate at 5fry/m2 and 10fry/m2 stocking densities. Nine concrete tanks and eighteen concrete tanks were used in experiment 1 and 2, respectively. The results indicated that abundance of natural food (phytoplankton) were significantly higher (P<0.05) in di-ammonium phosphate (DAP) fertilizer applied tanks compared to other treatments. Zooplankton diversity was higher in tanks applied with chicken manure, followed by tanks applied with DAP fertilizer and least in tanks with no fertilizer. Fry growth performance was higher in fertilized tanks compared to unfertilized tanks. At low stocking density (5fry/m2) fry had better growth performance compared to high stocking density (10fry/m2) across all fertilizer types. Survival rates were not significantly different (P>0.05) between chicken manure and DAP fertilized treatments across stocking densities though significantly differed (P<0.05) from the control. Water quality parameters were found to be within the optimum range for cat fish in both experiments. In conclusion, the study indicated that higher phytoplankton abundance are attained with DAP fertilized tanks and Zooplankton diversity were higher in chicken manure applied tanks. Therefore, it is recommended that for better growth and survival in aquaculture practices, catfish fry should be raised in DAP or chicken manure fertilized tanks at low stocking density as suggested by this study.