黑莓鲈(Pomoxis nigromacufatus)仔鱼饥饿试验及PNR的确定

Experimental Starvation on Pomoxis nigromacufatus Larvae and Definition of the Point of no Return

为确定黑莓鲈仔鱼的饥饿耐受能力及死亡不可逆点（PNR），采用实验生态学方法研究饥饿对黑莓鲈仔鱼摄食、生长与发育的影响。结果表明，在19．5～22．8℃水温条件下：①黑莓鲈仔鱼在6日龄开口摄食，8日龄卵黄囊消失，其混合营养期仅维持2 d 左右，属于易遭受饥饿胁迫鱼类；②仔鱼最高初次摄食率出现在9日龄，初次摄食期仔鱼的 PNR 发生在孵化后第11～12 d，仔鱼具有摄食能力的时间仅4～5 d，且在到达 PNR 后仅1 d 多即全部死亡，其耐受饥饿的能力较差；③在饥饿胁迫条件下的仔鱼对卵黄囊和油球的吸收进程明显慢于正常投喂组仔鱼，且随着饥饿程度的不断加深，仔鱼的生长发育趋于停滞甚至出现负增长；仔鱼在 PNR 期出现胸角，并且表现出一系列明显的由饥饿所导致的形态和行为学特征。

Effect of starvation on the feeding,growth and development of Pomoxis nigromacufatus larvae were investigated at 19.5-22.8℃ using an experimental ecological method.The tolerance to starvation and the point of no return （PNR）of P.nigromacufatus larvae were determined.The results showed that （a）the initial feeding of the larvae started at 6 days of age,the yolk sac disappeared at 8-day-old,the mixed dieting period was about 2 days, and the larvae were vulnerable to starvation stress;（b）the highest initial feeding rate of the larvae occurred when they were 9-day-old,the PNR was determined to be 11 to 12 days after hatching,their feeding last for merely 4 to 5 days,and they died one day after PNR;and （c）as compared with their counterparts under normal feeding,the starved larvae were slow to utilize yolk sac and fat globules,their growth became stagnant or regressive as the starvation continued,and they began to show pectoral angles at PNR with a series of apparent,hunger-induced morphological and behavioral characteristics.