草鱼幼鱼对不同缩结定置网片反应特性初探

初步研究了草鱼幼鱼对三种缩结定置网片的反应特性。结果表明;缩结对草鱼幼鱼在水槽内的分布特征没有显著影响,即无论在水槽内放置哪种网片,草鱼幼鱼均喜欢在网片邻近区域长时间停留,趋网、碰网尾次数及碰趋比也不随缩结不同而发生明显变化,但缩结对穿网尾次数、穿趋比和穿碰比有显著影响,扁形网目阻拦作用最大,长形网目次之,方形网目最小,推测穿网尾次数、穿趋比及穿碰比均与网目高度、鱼体高度之差和网目宽度、鱼体宽度之差的乘积成正比。

Preliminary Study on the Reaction of Juvenile Grass Carp to the Set Nets of Different Abating

The present paper deals with the reaction of juvenile grass carp to setnets using 3 kinds of abating. Results show that abating has no obvious effect on the distribution of juvenile grass carp in the tank, i. e. no matter what kind of net is put in the tank, juvenile grass carp, without exception, prefer to stay closly to the net for long duration. Differences in abating do not induce obvious change in the number of taxis, in number of touches, or in the ratio of touches to taxis. But abating has an obvious effect on the number of passing through the net, the ratio of passing through / taxis, and the ratio of passing through / touches. The study shows that flat nets produce the greatest obstruction effect therefore it's inferred, that the number of passing through, ratio of passing through / taxis and ratio of passing through / touches are without exception directly proportional to the product of differences in height between the mesh and the fish body, and differences in width between the mesh and the fish body. In addition, there are certain differences between the number of taxis, touches and passing through of juvenile grass carp.