Abstract:Effects of starvation on growth and survival in early life stage of rock bream Oplegnathus fasciatuswere studied. The results showed that PNR of newly hatched larvae appeared at 6～7 d, 6～7 d and 4～4.5 d respectively at temperatures of 18 ℃, 22 ℃ and 26 ℃. The first feeding time was delayed at low temperatures, for example, the larvae opened mouth on 4 d at 18 ℃ whereas mouth opened on 3 d at both 22 ℃ and 26 ℃.The first feeding rate reached the highest value (73.3%) at 22 ℃ but was lower at 18 ℃ and 26 ℃. Temperature had significant effects on the survival of the larvae and juveniles. When temperature was 18 ℃ and 22 ℃, half mortality time of early larvae appeared at 4～5 d while it was 2.5 d for 13 d old larvae and 1.5～2 d for 24 d old juveniles. The half mortality time of 45 d larvae was 6 d at 22 ℃ and 26 ℃. These results indicated that the capability of fish to tolerate starvation and temperature was enhanced with growth. Growth was delayed significantly (P＜0.05) by starvation; the fish in the experiment showed slow growth in total length and even negative growth in body weight. For example, the 30 d old juvenile fish lost 50% of body weight after starvation compared to the beginning, and the ratio was 10% for 45 d old juvenile. In conclusion, the results suggested that the 13 d old larvae were most sensitive to starvation and environmental changes.
