东海区夏、秋季大型水母分布区渔业资源特征分析

本文根据1999～2004年的夏季和秋季东海区大型水母和渔业资源的状况,分析了大型水母分布区内的渔业资源特征。结果表明大型水母夏季主要分布于30°30′～33°00′N间,秋季主要分布于32°00′N以北海域,并呈现由夏季到秋季逐渐往北转移的趋势;2003年是大型水母数量最高的年份,该年水母主要分布区内的渔业资源种类数最少,CPUE最低,Margalef种类丰富度指数也最低;2003年夏季水母高发区内渔获种类的优势度也较其它年份发生了显著变化,优势种变为黄;2003年水母高发区内带鱼、小黄鱼和银鲳的当龄鱼较少,银鲳的肥满度增加,小黄鱼的肥满度降低,而带鱼的肥满度未发生显著变化。本文对水母高发区内渔业资源变化的原因进行了初步解释,并对水母的防治措施提出了初步的建议。

The analysis on fish stock characteristics in the distribution areas of large jellyfish during summer and autumn in the East China Sea region

The fish stock characteristics in the distribution area of large jellyfish were analyzed in summer and autumn from 1999 to 2004 based on the jellyfish and fish stocks data. The results showed that jellyfish were mainly distributed in the sea area of 30°30′N～33°00′N in summer and north of 32°00′N in autumn, and gradually moved to the northern area from summer to autumn. The jellyfish was found the greatest quantity in 2003, whereas the fish species and CPUE were the smallest, and Margalef's species abundance index was the least too, in the main jellyfish distribution area in 2003. The dominance of fishes in the main jellyfish distribution area changed significantly; the dominant species altered to Lophius litulon in 2003. The percentages of juvenileTrichiurus japonicus, Pseudosciaena polyactis, and Pampus argenteus were less in the main jellyfish distribution area in 2003 compared with that in 2000. The condition factor of P. argenteus increased, but that of P. polyactis decreased, and that of T. japonicus was no remarkable change in 2003. The reasons for the changes of fish stock characters in higher jellyfish distribution area were preliminarily explained, and the control measures of jellyfish blooms were advised.