Effects of over stocking on the growth rate of Clarias gariepinus

The African catfish (Clarias gariepinus) were reared at four different stocking densities in a circular plastic bowls to evaluate the effects of over stocking on the growth rate of Clarias gariepinus. 140 fish were stocked at 10, 20, 30 and 40 with a mean of 8.5, 8.66, 9.2 and 9.15 respectively. The growth trial lasted for 92 days (June to August). The final mean weight of fish stocked at densities 10, 20, 30 and 40 were 153.1, 121.5, 96.6 and 68.6 (g) fish were with 10% body weight between the hour of 8.00 to 9.00am and 5.00pm to 6.00pm. Feed not consumed are siphoned out to avoid contamination of water which will be toxic to the fish. The corresponding mean values of specific growth rate were 3.05, 2.80, 2.62, and 2.26. The feed conversion ratio (FCR) was 5.91, 5.45, 5.14 and 4.76 and cumulative survival rates were 99.86, 99.65,96 .66 and 92.5%. The temperature ranges from 26.5 to 30.5°C. The pH range from 6.9 to ± 0.36 to 7.25 ± 0.22. The Dissolved oxygen (DO) was 2.65mg/l to 5.41 mg/l. The result revealed that over stocking had a significant effect on the growth rates of Clarias gariepinus. Fish held at the highest stocking density of 40 exhibited the lowest growth and survival rate.