Effect of different stocking density on nutrient utilization, growth performance and survival of African catfish (Clarias gariepinus, Burchell, 1822) fry in recirculatory system

Abstract

Management of C. gariepinus fry in recirculating tank is one modern technique applied for fish culture in Nigeria. Since, this system is gaining popularity nationwide there is a dare need to investigate appropriate stocking density as already established for both concrete tanks and earthen pond system. Clarias gariepinus fry (0.14±0.01 g) were reared in indoor recirculating tanks (60.5 m 3) at three different stocking rates 5000, 8000 and 12000 fry/tank as treatment LD, MD and HD respectively for a period of eight weeks. The experiment was duplicated and fish were fed 45% crude protein diet at 5% in four installments daily. The mean body weight gain and SGR decreased with increasing stocking density. The best growth performance (weight gain, length gain and SGR) was achieved in treatment LD. The lowest FCR (1.04±0.01) value was obtained in HD but show no significant difference (p>0.05) to other treatments. Percentage survival of the fish was significantly (p<0.05) affected by the stocking density with the highest value recorded in LD (86.8%). Waterquality parameters were within the recommended ranges throughout the experimental period. From this study, the stocking density of 5000 fry m -3 is recommended for efficient feed utilization, optimum growth performance and survival in a re-circulatory culture system.