影响漠斑牙鲆稚鱼的自残因子的研究

THE FACTORS AFFECTING CANNIBALISM IN SOUTH FLOUNDER PARALICHTHYS LETHOSTIGMA JUVENILES

漠斑牙鲆(Paralichthys lethostigma)稚鱼阶段,自残现象比较严重。本文以漠斑牙鲆稚鱼为实验对象,选取全长10.1—40.9mm的漠斑牙鲆进行试验观察。研究了密度、浑浊度、饥饿、个体大小差异对该幼鱼自残的影响程度。(1)密度、投饲量、个体大小差异对漠斑牙鲆稚鱼的自残行为影响极显著;高密度组的比低密度组自残现象严重;饱食组的自残率较1/3饱食投饲量组别的轻;个体大小差异是引起自残最重要的因子,当投喂不充足时,(10.1±0.4)—(20.3±0.3)mm组的自残现象最为严重自残死亡率为53%。(2)饥饿对自残行为影响显著,饥饿24h后自残死亡率为20%((15.0±0.4)mm组)。(3)浑浊度、饵料种类对自残行为影响不显著,在密度为20尾/L时,无浑浊度组稚鱼自残死亡率为8%,浑浊度组5%。

Laboratory experiments were conducted with P. lethostigma juveniles （total length 10.1-40.9mm） in different treatments. The results showed that Cannibalism occurred more frequently in hetreogeneous than in homogeneous size groups, the cannibal behavior at insufficient diet were marked higher than those at full diet, the stocking density had influence on the cannibal behavior of the young fish and the cannibal rate at high density was higher than at low density. （ 1 ） It suggested that the differences in body sizes was a main reason causing the cannibalism among the young fishes, and when the young fishes were insufficient diet in the group of （10.1 ± 0.4）-（20.3 ± 0.3）mm, the rate of cannibalistic death was 53 %. （2） Hungry had influence on the cannibal behavior of P. lethostigma young fishes which were hungry after 24h, and the rate of cannibalistic death was 20% in the group of 15.0 ± 0.4mm. （3） The kind of diet and the turbidity of water had no significant effect on cannibalism, when the stocking density was 20/L,the rate of cannibalistic death was 5% in the group of turbidity of water, and in the other was 8 %.