延迟投饵对卵形鲳鲹早期仔鱼阶段摄食、成活及生长的影响

Effect of delayed feeding on foraging, survival and growth of ovate pompano (Trachinotus ovatus) larvae during early development stage

  • 摘要: 利用人工繁殖产生的卵形鲳鲹(Trachinotus ovatus)初孵仔鱼,在水温(26.81.4) ℃、盐度28.20.8条件下,对延迟投饵0~6 d的卵形鲳鲹仔鱼的摄食、生长及其成活情况进行了研究。结果显示,仔鱼于3日龄开口,于开口的当天投饵及延迟投饵1、2、3、4和5 d,投饵后2 h内仔鱼的摄食率分别为15%、30%、50%、25%、15%和5%,每尾鱼的平均摄食量分别为0.4、0.6、1.3、0.6、0.3和0.1个轮虫。延迟投饵6 d一组仔鱼的摄食率均为0。延迟投饵0、1和2 d各组仔鱼的成活率相差不大,但延迟3 d以上仔鱼的存活率急剧下降。卵形鲳鲹仔鱼的初次摄食饥饿不可逆点(PNR)出现在仔鱼开口后4 d,开始投喂饵料的最佳时期应在仔鱼开口后的3 d之内。

     

    Abstract: Effects of delayed initial feeding on the foraging, growth and survival of artificial bred larvae of ovate pompano (Trachinotus ovatus) were studied under the water temperature of (26.81.4) ℃ and salinity of 28.20.8. The results showed that the larval mouth opened 3 days after hatching, and with the delayed initial feeding of 0, 1, 2, 3, 4 and 5 days, the feeding rate was 15%, 30%, 50% , 25%, 15% and 5%, respectively; the average consumption per larva within two hours was 0.4, 0.6, 1.3, 0.6, 0.3 and 0.1 prey, respectively. At day 6 of the delayed initial feeding, the feeding rate of all larvae was 0; there was no significant difference in the survival rate at the delayed initial feeding of day 0, day 1 and day 2 but the survivorship decreased abruptly while the delayed feeding lasted more than 3 days. The point of no return (PNR) occurred at 4 days after the larval mouth opened, which indicated that the optimum initial feeding time for the larvae was within 3 days after their mouths opened.

     

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