三峡库区大宁河鱼类的时空分布特征

为了解大宁河鱼类资源量及其分布特点，于2006年12月和2007年4月利用HTI Model 241鱼探仪对三峡库区大宁河进行了声学调查。结果表明：冬季鱼类密度显著高于春季，这与鱼类自身的繁殖越冬行为有关。统计分析显示，鱼类水平分布的差异与水深没有明显的相关性，可能主要由群聚行为引起。另外，冬季大宁河鱼类主要分布在中下层，上层和中下层的鱼类密度分布存在极显著性差异(p <0.01)；春季鱼类主要分布在中上层，中层和下层的鱼类密度分布差异显著(p <0.05)。大宁河鱼类在冬季和春季均属于成群分布，并且春季各层鱼类密度的变异系数高于冬季，这与水温和鱼类的防御机制有关。

Survey on temporal and spatial distribution of fish in the Daning River

To gain the biomass and distribution of the fish in Darting River, twice acoustic evaluation have been carried out by using the HTI Model241 fish detection equipment in the winter of 2006 and April of 2007. The density of fish was obvi-ous higher in winter than that in spring, which may be relate to the behavior of fish. Statistical analysis showed that differ-ence in horizontal distribution was not significantly correlated to water depth ; the variations of fish density in the Daning River might be caused mainly by aggregation activity of fish. In winter, there were very significant differences between sur-face and middle layers, and surface and bottom layers in fish distribution (p<0.01). In spring, average of fish density in middle was much higher than that in surface and bottom layers and obvious differences between middle and the other two layers were observed(p<0.05). The variations of fish density in spring were higher than that in winter, which have rela-tionship with the water temperature and recovery capability of fish.