黄海南部、东海北部小黄鱼饵料组成和摄食强度的变化

根据2001~2004年收集的黄海南部、东海北部的小黄鱼样品,应用研究鱼类摄食习性的常用方法,对小黄鱼的饵料组成和摄食强度的变化进行了研究。结果表明,小黄鱼摄食的饵料种类多达24种,鱼类和甲壳类是其主要的饵料类群,两者在食物中所占的重量百分比之和为93.7%。小黄鱼在不同生活时期的饵料种类和摄食强度变化较大。越冬期的摄食强度最低,为弱摄食期,3月以脊腹褐虾和七星底灯鱼为主;产卵期的摄食强度较高,为中强摄食期,产卵盛期的4月以长额刺糠虾和脊腹褐虾为主,产卵后期的5月以中华假磷虾、鰕虎鱼科和细长脚虫戎为主;索饵期的摄食强度较高,为强摄食期,6月以四盘耳乌贼、长蛸幼体、尖牙鲈和脊腹褐虾为主,7月以蓝圆鲹和虾蛄为主,10月以细条天竺鲷和带鱼幼鱼为主,11月以七星底灯鱼为主,12月以七星底灯鱼和鹰爪虾为主。与20世纪60年代初研究结果比较发现,小黄鱼食物组成发生很大的变化,由以往的浮游动物为主演变为目前的游泳动物为主;产卵时和刚产卵完的群体的摄食需求强烈,较以往的产卵群体停止摄食或少量摄食存在很大差异。

Variations in diet composition and feeding intensity of small yellow croaker Larimichthys polyactis Bleeker in the southern Yellow Sea and northern East China Sea

Based on the samples collected in the southern Yellow Sea and northern East China Sea from 2001 to 200d the paper bears on the variations in feeding intensity and diet composition of small yellow croaker. The results indicated that the diet species fed by small yellow croaker had 24 species, with fishes and erustaceans as the main groups, which accounted for 93.7% of the food weight. The diet composition and feeding intensity changed greatly in different life stages of small yellow croaker. The feeding intensity was the least in overwintering period which is feeble feeding period. The major diets were Crangon affinis and Benthosema pterotum in March. The feeding intensity was higher in spawing period, the mid-feeding period, and major diets were Acanthonmysis longirostris and C. affinis in peak spawning period in April. After spawning in May, the major diets were Pseudeuphausia sinica, Gobiidae and Themisto gracilipes. The feeding intensity was also higher in feeding period which is strong feeding period. Their major diet composition was Euprymna morsei, Octopus variabilis larvae, Synagrops japonicus and C. affinis in June, Decapterus maruadsi and Squilla oritoria in July, Apogon lineatus and Trichiurus japonicus larvae in October, B. pterotum in November, B. pterotum and Trachypanaeus curvirostris in December. Compared with the result of the early 1960s, the diet composition of small yellow croaker has greatly changed from zooplankton to nekton. The population at spawning and after spawning time has stong feeding demands, which have great differences compared to non- feeding or a little feeding in the past.