Abstract:A series of experiments have been conducted to study the effects of salinity and temperature on embryonic development and starvation endurance of newly hatched larvae of rock bream Oplegnathus fasciatus (T.& S.). Experiments were carried out in Qingdao Zhonghai Fishery Co., Ltd. from 2004~2007. Eggs were collected immediately after spawning and transferred into tanks for incubation. Salinity study was carried out in 2005, with treatmentsat salinities of 40，35，30，25，20，15，10 and 5.The results showed that the suitable salinities for embryonic hatching ranged from 20 to 35 with the most suitable range between 25～30, when hatching rates were all above 88%. Salinities above 40 or below 20 led to low hatching rate and prolonged hatching time. Temperature study was done in 2004,2005 and 2007, respectively. Taking into consideration the hatching rate,hatching time and deformity rate of the newly hatched larvae, it is deduced that the suitable temperatures for hatching ranged from 21～27℃ with hatching rates above 77%;most suitable temperatures were 23～25℃ with high hatching rates over 89% and low deformity rate of newly hatched larvae. Hatching time was negatively correlated with temperature while embryonic development speed was positively correlated with temperature. The threshold temperature for embryo development was calculated as 10.06℃, the effective accumulated temperature was 4053℃•h. In addition, Q10 value was calculated, and was found to accord with the experimental result. Newly hatched larvae were starved to death at 8 DAH with half death time appeared at 6 DAH;starvation had regative effects on larval growth.
