唐鱼仔鱼对饥饿的应对策略研究

STUDIES OF STRATEGY FOR RESPONSE TO STARVATION RISK IN THE LARVAE OF TANICHTHYS ALBONUBES

研究了延迟投喂对唐鱼（Tanichthys albonubes）仔鱼存活和生长的影响,探讨唐鱼仔鱼对饥饿的应对策略. 结果显示,在水温26.0±1.0℃条件下,唐鱼仔鱼在孵出后的2.5～3 d开口摄食,5 d卵黄消耗完毕. 18～25 d,延迟投喂0～3 d仔鱼的存活率在80.4%～93.3%间变动,各组间的差异不显著（p＞0.05）;延迟投喂4 d,仔鱼的存活率下降至50%;延迟投喂5 d,仔鱼的存活率极显著下降,只有30.0%左右. 延迟投喂6 d以上,仔鱼的存活率为0,表明在本实验条件下唐鱼仔鱼的不可逆点（PNR）为孵出后的9 d. 延迟投喂2 d开始,仔鱼的生长便受到不同程度的影响,延迟投喂3 d是仔鱼的生长低谷,延迟4～5 d,仔鱼反而得到不同程度的恢复. 25 d内,延迟投喂5 d仔鱼恢复到与正常投喂组接近的生长水平. 由此提出关于仔鱼应对饥饿对策的＂存活与生长交易临界点＂和＂生存机遇期＂两个观点,并对它们的生态学意义作了初步地探讨.

Effect of delaying fed on survival and growth of the larvae, and the strategy for response to starvation risk in the larvae of Tanichthys albonubes were investigated in this study. Results showed that, at water temperature 26.0 ± 1.0℃, the larvae begun to feed after hatching 2.5 - 3.0 days, and yolk - sac was consumed up within 5 days. At the age of 18 -25 days,survival rates of the larvae of delaying fed 0 -3 days waved from 80.4% to 93.3%, and there was no detectable difference among these larvae groups （p 〉 0.05） ;and the survival rates of the larvae of delaying fed 4 days ,5 days and above 6 days were reduced 50% ,30% and all died before the check time ,respectively. The point of no return （PNR） was 9th day after the larvae hatching. Delaying fed 2 days showed obvious reduction of total length growth comparing with the contol group. And delaying fed 3 days the length growth reduced remarkably ; delaying fed 4 - 5 d, the larvae resumed the total length growth. At the age of 25 days, delaying fed 5 days larvae total length were approaching the contrast groups; there was no detectable difference between them. Two opinions ＂the trade off of survival and growth＂ and ＂the period of the survival challenge＂ and their ecological significance were also discussed in this Paper.