Effect of Stocking Density on Production of Clarias Gariepinus (Tuegels) in Floating Bamboo Cages at Kubanni Reservior, Zaria, Nigeria

Abstract

The African Catfish (Clarias gariepinus, Teugels) were reared at three different stocking densities in bamboo-net cages to evaluate the effects of stocking density on growth, survival rate and food conversion ratio. Three hundred (300) fish with a total weight of 1.8Kg were stocked at 25, 50 and 75 fish/ m³ cage with a mean weight of 5.6±0.23g, 5.9±0.23g and 6.3±0.23 g/m³ respectively. The growth trial lasted for 150 days (May 2009 to October 2009). Twenty percent (20%) of the total biomass of the fish in each cage was weighed monthly and the bulk weights were calculated. Mortalities were recorded monthly. The final mean weights (±S.E) of the fish stocked at densities of 25, 50 and 75 fish/m³ cage were 828.0±1.83g, 774.0±20.18g and 693.0±34.20g. The corresponding mean values of Specific Growth Rate were 3.33, 3.25 and 3.43. Temperatures ranged between 24.5⁰C - 32.6⁰C while salinity ranged between 24 - 95ppm. The Feed Conversion Ratio (FCR) was 4.99, 4.73, and 3.43, and cumulative survival rates were calculated as 99.84, 99.66 and 99.50% respectively. The results revealed that stocking density had a significant (P>0.05) effect on growth and survival rates of Clarias gariepinus. Fish held at the highest stocking density exhibited the lowest growth and survival rate. Cages with 50fish/m³ stocking density had the best production with total final weight (38.67Kg) and profit index (3.27) compared to other treatments (P>0.05).

Keywords: Stocking density, bamboo-net cages, profit index, survival, growth, Clarias gariepinus