The influence of food particle size on gastric emptying and growth rates of fingerling African catfish, Clarias gariepinus Burchell, 1822

This study investigates the effect of feed particle size on gastric evacuat ion and growth of fingerling African catfish, Clarias gariepinus. Fish (0.9 7 +/- 0.07 g) held in 40-cm diameter tanks at a stocking density of 5 fish L-1 (25 fish per tank) were presented with one of four sizes of food partic les (1, 1.5, 2 and 3 mm diameter). Gastric evacuation rate could be describ ed by an exponential function with small feed particles being evacuated mor e rapidly: values of 0.076, 0.054, 0.047 and 0.029 were observed for fish f ed 1 mm, 1.5 mm, 2 mm and 3 mm food particles, respectively. Growth rates w ere highest for fish fed the 1.5 and 2 mm pellets. Based on these findings, recommendations are made on the optimum food particle size for C. gariepin us fingerlings.