Effects of low salinity stress on growth of juvenile Paralichthys olivaceus.

To investigate the growth of juvenile brown flounder(Paralichthys olivaceus) under low salinity stress,we cultured the juveniles at salinity 5 for 0 week(control),1 week,2 weeks,3 weeks and 4 weeks,respectively,and then changed the salinity to 19 immediately.The experiment last 10 weeks.It is found that the average body weight of the juveniles at low salinity is significantly smaller than that in the control only in 1st week.Significant difference in daily growth coefficient among different treatments is found in 3rd and 5th week.There is no significant difference in the body weight and daily growth coefficient during the other experimental periods.The feeding rate of the juveniles under low salinity stress is slightly lower than that in the control.However,in recovery periods,no higher feeding rate is observed at low salinity.During the whole experimental period,the average feed conversion efficiency of the juveniles at low salinity is slightly higher than that in the control.The results indicate that low salinity(5) imposes no long-term effects on the growth of juvenile brown flounder and compensatory growth can not be achieved by culturing the flounder at low salinity for a long period.