鳀鱼摄食习性的季节变化

Seasonal Variation in Feeding Habits of Engraulis japonicus

以2008年5月、8月、11月和2009年2月在东海和黄海采集到的633尾鳀鱼为研究对象,对其胃含物进行了分析,应用聚类分析、单因素方差分析和列联表检验等方法,对鳀鱼的食物组成和摄食强度的季节变化进行了研究。结果表明,鳀鱼的主要饵料生物种类有16种,太平洋磷虾是其最重要的饵料。其食物组成存在季节差异,按相对重要性指数(IRI%)排序,鳀鱼在春季以太平洋磷虾、小拟哲水蚤、细足法虫戎和长尾类糠虾幼体为主要食物;在夏季以太平洋磷虾、大眼蛮、细足法为主食;在秋季以太平洋磷虾和美丽大眼剑水蚤为主食;在冬季太平洋磷虾、美丽大眼剑水蚤、长尾类糠虾幼体、中华哲水蚤和丽隆剑水蚤为主食。统计分析检验表明,鳀鱼鱼的平均胃饱满度系数有显著的季节变化(P<0.01),春季和秋季的摄食强度较大,而夏季和冬季的摄食强度较低。

In the present papers, a total of 633 specimens of Engraulis japonicus were sampled from sea- sonal surveys in the East China Sea and Yellow Sea from May 2008 to February 2009. The diet composition and the feeding intensity, which were analyzed by applying the cluster analysis, one-way ANOVA and Kruskal-Wallis test, varied significantly different among seasons. The results showed that 16 main prey species were ingested by E. japonicus, while Euphausia pacifica constituted the dominant prey. The diet composition varied with season, as indicated by the relative importance index, E. pacifica, Paracalanus parvus, Themisto gracilipes, and Macrura mysis la^ae were the dominant prey in spring, whereas E. pacifica, Lestrigonus macrophthalmus, T. gracilipes, in summer, E. pacifica, Corycaeus speciosus in autumn, E. pacifica, C. specio-sus, M. mysis larvae, Calanus sinicus, Oncaea venusta in winter. The mean stomach fullness index, which were analyzed by applying the Kruskal-Wallis test, varied significantly among different seasons （P〈0.01）. It indicat- ed that the feeding intensity was the highest in spring and autumn, while the lowest in summer and winter.