东海区短鳄齿鱼摄食生态的初步研究

Preliminary study on feeding ecology of Champsodon snyderi in East China Sea region

根据2008年5月～2009年2月"东海区主要渔场重要渔业资源的调查与评估(26°00′～35°00′N,120°00′～126°30′E)"课题调查的渔获样品,对东海区短鳄齿鱼(Champsodon snyderi)的摄食生态进行了初步研究。结果表明:东海区短鳄齿鱼属于浮游动物食性,兼食游泳动物;其主要饵料生物为太平洋磷虾(Euphausia pacifica)、细螯虾(Leptochela gracilis)、七星底灯鱼(Benthosema pterotum)和麦氏犀鳕(Bregmaceros macclellandi);主要食物种类的优势度随体长段不同而变化,食物种类分化明显,符合"最佳摄食理论";短鳄齿鱼食物种类的季节替代明显,更替率尤以春季为高,达100%,其余三季相对接近;不同区域出现的饵料生物的种类自北而南递增,区域间食物种类的相似性系数均低于50%,表明短鳄齿鱼食物种类的区域差异明显,其中又以北部与其他两区的差异最大;短鳄齿鱼的年空胃率为16.34%,不同季节、区域和体长组的空胃率变动幅度也较小;短鳄齿鱼的年平均胃饱满指数为27.13‰,四季呈高低相间分布,并以冬季最高春季最低;平面分布与空胃率态势相同,自北而南递增,不同体长组的胃饱满指数差距甚小。

The feeding ecology of Champsodon snyderi in the East China Sea region was investigated based on the material from the survey of the East China Sea region from May 2008 to February 2009. The results showed that C. snyderi could be classified as a zooplankton carnivorous predator, as well as fed on nekton; the main food species of C. snyderi include Euphausia pacifica, Leptochela gracilis, Benthoserna pterotum and Bregrnaceros macclellandi. The dominance of main food species changed with changes in body length, and the species of food constituent were different obviously, which is consistent with the ＂optimum foraging theory＂. The seasonal changes of food species were obvious. The replacement rate reached the highest of 100% in spring and close among other three seasons. The species of food constituent were increased from the north to the south. The similarity index was all below 50% between areas, suggesting that the regional differences of the species of food constituent were very significant. The difference between the north and other two areas was the most. The yearly empty stomach rate of C. snyderi was 16.34%. The changes of empty stomach rate in different seasons, areas and body length groups were little. The yearly mean stomach fullness index was 27.13%0. The rate was the highest in winter and lowest in spring, increased from the north to the south, but was very close among different body length groups.