Comparative Effect of Stocking Densities and Feeding Levels on Monthly Growth Response of Hybrid Catfish (Heterobranchus longifilis x clarias gariepinus) in Collapsible Tanks

The comparative effect of stocking densities (SD) and feeding levels (FL) on growth response of Clarias gariepinus was examined for 12 months in collapsible tarpaulin tanks. Two hundred and forty (240) fingerlings spawned at the hatchery complex of Fisheries and Aquatic Environmental Management were used in a factorial experimental design consisting of five (5) different stocking densities (SD) and three (3) feeding levels (FL). SD were 100 fish/0.25 m3 , 75 fish/0.25 m3 , 38 fish/0.25 m3 , 18 fish/0.25 m3 , and 9 fish/0.25 m3 . Similarly, the three feeding levels established were: 1% Fresh Body Weight (FBW), 1.5% FBW and 2% FBW fed thrice daily. Each treatment was triplicated. Results show that SD at 100 fish/0.25 m 3 had the highest monthly Mean Weight Gain (MWG) (1165.8 g) while SD 18 fish/0.25 m3 showed the least MWG (604.2 g) for FL 1%. At FL 1.5%, the trend was more uniform in progression with SD 75 fish/0.25 m3 having the highest MWG and SD 38 fish/0.25 m3 as the least in MWG (896.8 g and 709.8 g) respectively. FL 2% had MWG values from SD 75 fish/0.25 m3 and SD 38 fish/0.25 m3 as highest and lowest respectively (837.1 g and 836.3 g). For Specific Growth Rate (SGR) at 1% FL across all SD, there was a sharp increase in month May and a gradual decline through to the end. Specific Growth Rate at FL 1.5%and FL 2% followed a similar trend as in SGR of FL 1%. The values were notably higher in May and declined progressively to the end. Generally, SD 75 fish/0.25 m3 and FL 1.5% gave the best MWG; hence fish for intensive culture can be carried out using tarpaulin tanks at high stocking density 75 fish/0.25 m3 for maximum performances in growth.

Keywords: Stocking density, feeding level, heteroclarias, hybrid catfish, specific growth rate.