Influence of Culture Water Draw-off on Growth of the African Catfish (Clarias gariepinus, Burchell 1822) cultured under Integrated System

Abstract

An experiment was carried out over a period of 10 weeks to investigate the influence of culture water draw-­‐off on growth and feed utilization of the African catfish. Two similar fish culture tanks (designated A and B) were stocked with juveniles of African catfish at 43 fish per m³. The fish were fed twice daily at 3 % body weight. 0.06 m³of culture water was removed at 3-­‐day intervals from tank B to irrigate Okra plot and the tank was replenished with an equal amount of freshwater. Culture water was not removed from tank A till both tanks were replenished with freshwater at 14-­‐day intervals. Selected water quality, growth and feed utilization parameters were measured just before replenishing. The selected water quality parameters were within the recommended range for fish culture except for nitrite and dissolved oxygen. The water quality, growth performance and feed utilization parameters were better in tank B, with periodic culture water removal than in tank A, without water draw-­‐off. Average final weight, weight gain, daily weight gain, specific growth rate, percentage survival and feed conversion ratio were; 165.06 g, 95.07 g, 1.36 g/day, 0.01 %/day, 95.30 % and 2.40 in tank A and 238.22 g, 171.62 g, 2.45 g/day, 0.02 %/day, 94.87 % and 1.82 in tank B respectively. Periodic draw-­‐off of culture water had positive effect on the cultured fish as evident in better performance indices recorded in this study.