延迟投饵对花尾胡椒鲷仔鱼摄食、生长和存活的影响

Effects of Delayed Initial Feeding on Foraging,Growth and Survival of Larval Yellow Spotted Grunt(Plectorhinchus cinctus)

2001年4月至5月在集美大学海水养殖试验场对延迟投饵的花尾胡椒鲷仔鱼的摄食、生长与存活进行了观察.结果表明:在盐度24.0～24.8,温度18.5～22.8℃时,仔鱼4日龄开口.开口当天投饵,仔鱼未摄食.仔鱼延迟投饵1、2、3、4d时,投饵后2h内的摄食率分别为65%、60%、25%、15%,投饵后2h内平均每尾仔鱼的摄食量分别为0.95、0.80、0.35、0.20个轮虫,而延迟投饵5d、6d的仔鱼的摄食率均为0.完全投饵组6日龄、8日龄仔鱼的全长分别比完全饥饿组仔鱼长0.068mm和0.222mm.在仔鱼开口后4d内,各组仔鱼的死亡率差异不大;开口4d后,各组仔鱼死亡率差异越来越大;开口后第6d,延迟投饵0～3d的仔鱼的存活率在43.3%以上,而延迟投饵4d以上的各组仔鱼的存活率均低于16.7%.花尾胡椒鲷仔鱼在开口后第4d进入PNR期.

The foraging, growth and survival of larval Plectorhinchus cinctus of delayed initial feeding was investigated in the present study.The results showed that,at temperature of 18.5～22.8℃ and salinity of 24.0～24.8,the larval mouth open on the 4th day after hatching,but they couldnt forage.With delayed initial feeding of 1 day,2 days,3 days and 4 days,the feeding rates of larvae were 65 %,60 %,25 % and 15 %,respectively;the feeding amount of prey per larvae in two hours was 0.95,0.80,0.35 and 0.20 individually.The feeding rates of larvae delayed feeding of 5 days and 6 days was 0.On the 6th and 8th days after hatching,total length of the larvae feeding without delayed was 0.068mm and 0.222mm longer than that of not feeding.The results also indicated that,within 4 days after mouthopening,the mortality rates of all the larvae were not significantly different.While 4 days after mouthopening later,the difference was much more significant.And on the 6th day after mouthopening,the larvae survival rates of larvae feeding delayed 0～3 days were all over 43.3%,while that of delayed over 5 days below 16.7%.The Plectorhinchus cinctus larvaes PNR was on the 4th day after mouthopening.