Abstract: Specific growth rate(SGR), survival rate, food intake(FI), food conversion ratio(FCR), oxygen consumption rate(OR) and ammonia excretion rate(AR) were determined in juvenile marbled rockfish Sebastisucus marmoratus with body weight of(3.65±0.82)g in an indoor tank of 6.5 m×2.5 m×(water depth 1.3 m) with a salinity of 5, 7.5, 10, 15, 20, 25, and 30 at water temperature of 19-28 ℃ for 8 weeks in order to investigate the effect of salinity on growth and metabolism of marbled rockfish. The results showed that the juveniles had better growth at a salinity of 10, 15 and 20, with survival rate of 97.50%, 98.33% and 91.67%, and SGR of 1.904, 2.001 and 2.077%/d, respectively. However, there was significantly lower survival rate at a salinity of 5(0%), 7.5(19.17%) and 30(76.67%) than that at a salinity of 10, 15, 20(P<0.05). The FCR was varied from 1.230 to 1.367, significantly lower at water salinity of 15, 20 and 25 than at 7.5 and 30(P<0.05), without significant difference among the salinity at 10, 15, 20 and 25(P>0.05). The FI was shown to be changes from 1.282%/d to 2.157%/d during the experiment, significantly lower at water salinity of 15, 20 and 25 than at water salinity of 7.5 and 30(P<0.05), without significant difference between each group at water salinity of 10, 15, 20 and 25(P>0.05). The OR and AR was increased with the increase in water salinity within the water salinity range of 7.5-30 first, and then decreased with the increase in water salinity, the peak values 0.137 mg/(g·h), and 10.406 μg/(g·h) at a salinity of 15 and 25. The OR(y)showed relationship with water salinity(x) as y=-0.0002x^2+0.0091x+0.0512(R^2=0.9287), with O/N value of 12.160-16.415 in the fish. In conclusion, marbled rockfish juveniles have strong salinity tolerance and can adapt to low salt or high salt water by regulating physiological metabolism level, and it is suggested that a salinity of 15-25 be the optimum salinity range for growth and metabolism in marbled rockfish.
2019, Vol. 34 
