饥饿对条石鲷仔稚鱼生长发育的影响

Effects of starvation on the growth and development of larval and juvenile rock bream Oplegnathus fasciatus

中文关键词: 条石鲷  仔稚幼鱼  饥饿  生长

英文关键词: Rock bream Oplegnathus fasciatus L.  Juvenile fish  Starvation  Growth

中文摘要:

      采用实验生态学方法研究了饥饿对条石鲷仔稚幼鱼的影响。结果表明，水温18、22和26 ℃时，初孵仔鱼的PNR点分别出现在6～7 d、6～7 d和4～45 d。仔鱼开口摄食时间随温度降低而滞后，22 ℃时初次摄食率最高，26 ℃时初次摄食率降至50%以下。温度对仔稚幼鱼耐饥饿的能力影响明显，18和22 ℃时，前期仔鱼半数死亡时间为4～5 d，而13日龄仔鱼半数死亡时间为2.5 d，24日龄稚鱼的为1.5～2 d，实验鱼饥饿3 d后，大部分已经不能恢复摄食。在26 ℃时，前期仔鱼和13日龄仔鱼的半数死亡时间为1.5 d，24日龄稚鱼为2～2.5 d，而45日龄幼鱼在22和26 ℃时半数死亡时间都为6 d，表明随着生长发育，苗种对饥饿耐受能力明显增强。饥饿对条石鲷幼鱼的生长影响显著（P＜005），饥饿条件下的仔鱼全长和体重增加远远低于对照组，甚至出现体重的负增长，30日龄幼鱼在饥饿条件下的体重损失率达到50%以上，而45日龄幼鱼饥饿后的体重损失率约为10%，13日龄仔鱼阶段是条石鲷早期生长发育阶段中较为敏感的阶段。

英文摘要:

      Effects of starvation on growth and survival in early life stage of rock bream Oplegnathus fasciatuswere studied. The results showed that PNR of newly hatched larvae appeared at 6～7 d, 6～7 d and 4～4.5 d respectively at temperatures of 18 ℃, 22 ℃ and 26 ℃. The first feeding time was delayed at low temperatures, for example, the larvae opened mouth on 4 d at 18 ℃ whereas mouth opened on 3 d at both 22 ℃ and 26 ℃.The first feeding rate reached the highest value (73.3%) at 22 ℃ but was lower at 18 ℃ and 26 ℃. Temperature had significant effects on the survival of the larvae and juveniles. When temperature was 18 ℃ and 22 ℃, half mortality time of early larvae appeared at 4～5 d while it was 2.5 d for 13 d old larvae and 1.5～2 d for 24 d old juveniles. The half mortality time of 45 d larvae was 6 d at 22 ℃ and 26 ℃. These results indicated that the capability of fish to tolerate starvation and temperature was enhanced with growth. Growth was delayed significantly (P＜0.05) by starvation; the fish in the experiment showed slow growth in total length and even negative growth in body weight. For example, the 30 d old juvenile fish lost 50% of body weight after starvation compared to the beginning, and the ratio was 10% for 45 d old juvenile. In conclusion, the results suggested that the 13 d old larvae were most sensitive to starvation and environmental changes.