The effects of delayed initial feeding on the growth and survival of silver perch, Bidyanus bidyanus (Mitchell, 1838)

Abstract

Three sets of experiments were conducted to determine the point of no return (PNR), growth rate, and survival of silver perch (Bidyanus bidyanus) larvae. In each of the experiments, the larvae were exposed to different initial feeding delays, starting from yolk sac exhaustion at 4 days post hatching (dph). The PNR experiment was conducted for eight days to test different delayed initial feeding of 0, 1, 2, 3, 4, 5, and 6 days respectively, while growth and survival experiments were conducted for 20 days at 0, 1, 2, 3, and 4 delayed initial feedings, with unfed larvae as a control group. The result showed that the onset of feeding occurred at 5 dph and PNR was detected between 8 and 9 dph. The specific growth rates at 0, 1, and 2 days of delayed initial feeding were significantly higher (p < 0.05) than the other treatments. The initial feeding also affect the survival rate where the delay of 0 and 1 day were significantly higher (p < 0.05) than the other treatments. These results indicate that initial feeding at 5 and 6 dph has an advantage in growth rate over initial feeding at 7 and 8 dph. Because larval survival at 5 dph initial feeding was higher than at 6 dph, the initial feeding of silver perch larvae should start at 5 dph.