大口鲇苗种同类相残的研究

Studies on the cannibalism among Silurus meridionalis larvae

在不同条件下 ,对大口鲇苗种 (全长 1.0 7～ 9.4 3cm)进行同类相残研究。结果表明 ,饵料缺乏时的相残率均显著地高于饵料充足时 (P <0 .0 1,N =8)。放养密度对大口鲇苗种的相残行为有影响。大口鲇苗种相残最严重的时期是在平均全长 1.0 7～ 2 .68cm阶段。当平均全长达 6.71cm以上时 ,相残行为较弱。苗种间个体大小存在差异 ,尤其是大规格苗种间出现个体大小差异时 ,相残行为较严重。饵料缺乏是导致大口鲇苗种发生同类相残的主要原因 ,高放养密度和个体大小的差异会诱发和促进同类相残的发生。

The study was conducted with Silurus meridionalis larvae (total length 1.07～9.43 cm) in different treatments under full diet and insufficient diet. The results showed that the cannibal rates at insufficient diet were markedly higher than those at full diet (P<0.01, n=8). The stocking density had influence on the cannibal behavior of the larvae that the cannibal rate at high density was higher than that at low density. The cannibalism of the S.meridionalis larvae was most serious at total length 1.07～2.68 cm, but the cannibal rate was much lower when the average total length was over 6.71 cm. Differences in body sizes may lead to serious cannibalism especially among big sized larvae. It is suggested that insufficient diet is a main reason causing the cannibalism among S. meridionalis larvae; high stocking density and differences in body sizes can induce and stimulate the cannibalism.