INFLUENCE OF STOCKING DENSITY ON THE GROWTH AND SURVIVAL OF POST FRY OF THE AFRICAN MUD CATFISH (CLARIAS GARIEPINUS)

ABSTRACT

The experiments were conducted on the influence of stocking density on growth and survival of post fry of the African mud catfish, Clarias gariepinus. Clariasg gariepinus post fry were stocked at the rate of 5, 10, 15, 20, and 25 post fry/ 30l litres of water. The post fry were fed twice daily with a commercial catfish feed( Skrettings) at 3% body weight. The survival, mean total length, mean body weight, condition factor, specific growth rate and performance index were found to be density dependent. Water temperature ranged between 28.73±0.91 °C and 29.95±0.64 °C. The pH mean values in all tanks ranged from 6.50±0.26 to 6.76±0.40 while the dissolved oxygen ranged between 6.21±0.89 and 7.15±0.27. Values of the temperature and dissolved oxygen were relatively lower in higher density media (T4 and T5). The values of temperature, dissolve oxygen and other observed water quality were within acceptable ranges for fish culture practice in this study. This factor probably enhanced the observed good growth and condition of the test fish throughout the experimental period. There was a general increase in weight and length in all fish during the experimental period. The mean weight gain of fish in tank one was 24.60±0.44g, followed by tank three (22.65±0.19g), tank two 22.58±0.23g, and tank four (21.23±0.65g) while tank five recorded 21.00±0.30g. Specific growth rate (SGR) for tank four (3.30±0.01 %.day-1) was lower than that of tank 3 (3.28±0.00 %.day-1), tank 5 (3.47±0.00 %.day-1) and tank1 (3.49±0.10 %.day-1) respectively. Condition factor that ranges from 0.72±0.00 (tank 1) to 0.80 ± 0.02 (tank 5) were observed. It is concluded that increaseddensity impacts on growth and survival of the fish, a consequence of increased activity (frequent surfacing, feeding and swimming) and aggressiveness.