斑鳜仔鱼饥饿试验及不可逆点的确定

Starvation Test on Siniperca scherzeri Larvae and Acertaining the Point of No Return

在水温（23±1）℃条件下研究饥饿对斑鳜（Siniperca scherzeri）仔鱼生长、形态和行为的影响,确定其初次摄食饥饿不可逆点（the point of no return, PNR）和初次投喂最佳时间.结果表明：斑鳜仔鱼孵化后3 日龄开始摄食外源食物,进入混合营养期;7 日龄油球吸收完毕,进入外源营养期,混合营养期仅4 d.饥饿状态下,仔鱼生长与卵黄囊吸收密切相关,全长基本维持恒定,4 日龄出现自残现象,但仔鱼身体发黑、头大身瘦、后脑部下陷;集群性、初次摄食率与饥饿时间呈负相关;初次摄食时间在3 日龄,仅为5%,高峰期出现在6 日龄（油球即将完全吸收）,可达85%,PNR 期为7～8 日龄;仔鱼具有初次摄食能力的时间为4～5 d,仔鱼初次摄食最佳投喂时间在5 日龄左右.

Under the water temperature of(23 ± 1) ℃, the effects of starvation on growth, morphology and behavior were studied, and the point of no return(PNR) for the larvae of Siniperca scherzeria and the best time for initial feeding were ascertained. The results showed that the developmental stage was a period of mixed nutrition when the larvae began to feed on the third day after hatching. The larvae came into the stage of nutrition outside completely on the 7 days old. The period of mixed nutrition lasted only 4 days. The total length generally maintained constant when the larvae were in a state of starvation, while there was close relation between the yolk sac and growth changes. The stagnated larvae were black and thin,which had bigger heads and slender bodies; the gregariousness and ability of initial feeding had negative correlation with the starvation time. The initial feeding time of Siniperca scherzeria was in 2 d, and the initial feeding rate was 5%, but the tiptop initial feeding rate of the larvae which reached 85% occurred on the 6 days old when the oil globes were sufficiently absorbed. The point of no return(PNR) was in 7 d to 8 d, while the initial feeding rate was 50%. The initial feeding time of the larvae lasted 5-6 days, but the best time for initial feeding was on the third day after hatching.