温度对花斑副沙鳅仔鱼发育、摄食及不可逆点的影响

2011年4～5月,研究了温度对花斑副沙鳅(Parabotia fasciata)早期仔鱼的发育、初次摄食时间、群体摄食率及不可逆点(PNR)的影响。结果发现,花斑副沙鳅仔鱼出膜后2 d已开始摄食;初次群体摄食率最高值出现在卵黄囊耗尽后的1～2 d,花斑副沙鳅仔鱼的摄食强度随温度升高而增大。仔鱼抵达PNR的时间随温度升高而缩短:22℃时,仔鱼的PNR出现在出膜后的8.0～9.0 d;26℃时,PNR为7.0 d;28℃时,PNR为5.5 d;30℃时,PNR为5.0 d。最大初次摄食率至PNR之间为不可逆饥饿期,22℃时为3.5 d,30℃时仅为1.5 d,说明温度越高,仔鱼耐受饥饿的能力越差,越不利于仔鱼的存活。研究认为,温度对花斑副沙鳅仔鱼发育、摄食及不可逆点的影响较大;在苗种培育过程中,应根据温度确定投饵时间,适时投饵对仔鱼的成活显得尤其重要。

Effect of Temperature on Development, Feeding and the Point of No Return of the Larvae of Parabotia fasciata

Studies were conducted to examine the effects of temperature on larval and juvenile development,initial feeding timing,the group feeding rate and the point of no return(PNR) of the larvae of Parabotia fasciata during April to May,2011.The results showed that the larval mouth opened 2 days after hatching and the group feeding rate peaked 1-2 days after the yolk sac exhaustion.The feeding intensity of the larvae of P.fasciata increased as the temperature rose.The time the larvae of P.fasciata reaching PNR shortened as the temperature rose,PNR appeared in 8.0-9.0 days after hatching at 22℃,in 7.0 d at 26℃,in 5.5 d at 28℃,and in 5.0 d at 30℃.The period between the feeding ratio reaching the peak and PNR is the starvation phase of no return.At 22℃,the starvation phase of no return lasted 3.5 days while that of 30℃ lasted 1.5 days.These results showed that the higher the temperature,the lower the larvae starvation endurance and the lower the survival rate.The study proves that temperature has a great effect on development,feeding and the point of no return of the larvae of P.fasciata.At different temperatures,proper feeding timing is of great importance to the survival of the larvae of P.fasciata.