太湖银鱼和主要鱼类渔获量间的相关分析

Analysis on the correlation between the catch of ice fish and main fishes in Lake Taihu

根据太湖1973-2002年连续30年的鱼类渔获量统计资料,研究了太湖银鱼和主要鱼类渔获量间的相关关系。并根据2004-2005年的食性调查初步结果对相互关系的机制进行了分析。简单相关分析表明,太湖银鱼和鲌鱼、鲢鳙鱼渔获量间的正相关关系均达到极显著水平;偏相关分析表明,太湖银鱼和鲌鱼渔获量间的正相关关系达到极显著水平,和其它鱼类渔获量间的正相关关系达到显著水平,和鲢鳙鱼渔获量间的正相关关系虽然没有达到显著水平,但有一致趋势;简单相关和偏相关分析均表明,太湖银鱼和和鲚鱼渔获量间的相关关系均没有达到显著水平。分析认为:太湖银鱼渔获量的变化除受捕捞强度及环境理化等因素影响外,鲌鱼通过捕食调节,可能降低了鲚鱼和银鱼的食物竞争强度,从而有利银鱼增加;鲢、鳙鱼通过和鲚鱼的食物竞争,从而间接促进了银鱼种群数量发展。

Based on the statistic data of fish catches from 1973 to 2002 in Lake Taihu, the correlation between catches of ice fishes and main fishes was analyzed. There was positive correlation between catches of ice fish and topmouth culter （Erythroculter ilishaeformis Bleeker and Erythroculter mongolicus Basilewsky） at a very significant level （ P 〈 0.01 ） in bivariate correlations and partial correlations;there was also positive correlation between catches of ice fishes and silver carp （Hypophthalmichthys molitrix Valenciennes ） and bighead （Aristichthys nobilis Richardson） at a very significant level （P 〈 0.01 ） in bivariate correlations. The conclusion was that： except for the effects such as overfishing, physical and chemical factors on the changes of ice fish catches, topmouth culter probably enhanced ice fishes by preying on lake anchovy （ Coilia ectenes taihuensis Yen et Lin） and then reduced its food competition with ice fishes;silver carp and bighead probably facilitated ice fishes by competing with lake anchovy.