东海有尾类数量分布

根据1997~2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,探讨了东海有尾类数量分布和季节变化。结果表明:秋季有尾类丰度最高,均值为149 ind/100m3,夏季38 ind/100m3,冬季20 ind/100m3,春季9 ind/100m3;有尾类数量在冬春夏季与水温和盐度相关关系不显著,秋季与表温有显著的正相关关系。有尾类数量季节变化机制具有暖水种的特征,这些特征形成与其优势种适温适盐特性有密切的关系。东海有尾类的数量波动,与东海暖流势力消长有密切的联系,也同暖流势力从夏到秋季维持一段时间有密切的关系。在东海,暖流势力较强的海域往往可以成为有尾类高丰度分布区域。秋季有尾类高分布区出现,对东海北部外海绿鳍马面鲀(Navodon septentrionalis)渔场和东海南部的带鱼(Trichiurus lepturus)和日本鲭(Scom ber japonicus)等多种经济鱼类渔场的形成有重要意义。

Abundance and distribution of Appendicularia in the East China Sea

Based on the data of four seasonal investigations in the East China Sea(23°30′-33°N,118°30′-128°E)from 1997 to 2000,the distribution and the seasonal changes of Appendicularia abundance,their dynamics and relationship with fishing grounds were discussed.The results indicated that the total abundance of Appendicularia peaked in autumn with an average value of 149 ind./100m~3,38 ind./100m~3 in summer,20 ind./100m~3 in winter and 9 ind./100m~3 in spring.The total abundance in spring,summer and winter showed no significant correlation with water temperature and salinity,while the abundance had significant positive correlation with surface water temperature in autumn.Appendicularia is characterized by warm water species.It was found that the formation of characteristics had a close relation with the dominant species adapting to different temperatures and salinity.The variation of Appendicularia abundance was closely linked with ebb and flow of warm current in the East China Sea.Its peak abundance in autumn also associated with the stay of warm current from summer to autumn.The occurrence of high abundance area of appendicularians in autumn in warm current waters such as Tsushima and Kuroshio plays an important role in forming the fishing grounds for Navodon septentrionalis in the north of offlying sea and Scomber japonicus and Trichiurus lepturus in the south of offlying sea.