Effect of Stocking Density on Production of <i>Clarias Gariepinus</i> (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