东海糠虾类数量分布

The abundance distribution of mysids (Mysidacea) in the East China Sea

根据1997-2000年东海23°30′～33°00′N、118°30′～128°00′E海域4个季节海洋调查资料，探讨了东海糠虾类的数量波动、相应的动力学过程及与渔场的关系。结果表明：东海糠虾类秋季丰度最高，均值为10ind·10^-2m^-3，春季次之（5ind·10^-2m^-3），夏季最低（1ind·10^-2m^-3）；春季的漂浮囊糠虾（Gastrosaccus pelagicus）、夏季的极小假近糠虾（Pseudanchialina pusilla）、秋季的四刺端糠虾（Doxomysis quadrispinosa）和冬季的中华节糠虾（Siriella sinensis）对糠虾类总丰度变化的贡献较大。冬夏季不同优势种间对总丰度的贡献值较为接近，春秋季则有明显的差异。糠虾类春季和4季总丰度与底层水温线性相关；冬夏季与底层盐度相关；秋季与表层水温和10m层水温相关。东海糠虾类的数量波动，与东海沿岸河流的径流量，特别是长江径流势力消长有密切的联系，也与东海暖流势力从夏季到秋季维持一段时间有密切的关系。秋季糠虾类高分布区出现，对东海北部外海鲐鳕鱼渔场和闽南一台湾浅滩渔场的形成有重要的意义。

Based on the data of four seasonal investigations in the East China Sea （23°30′～33°00′N、118°30′～128°00′E）from 1997 to 2000, the distribution of mysid abundance, its seasonal changes and dynamics, and relationship with fishing ground were discussed in this paper through qualitative and quantitative methods. Results showed that the total abundance of mysids peaked in autumn with average value, 10 ind·10^-2m^-3, and it was the second highest value, 5 ind·10^-2m^-3 in spring and the lowest, 1 ind·10^-2m^-3 in summer. Since C, astrosoccus pelagicu, in spring, Pseudanchialina pusilla in summer and Doxomysis quadrispinosa in autumn and Acamhomysis sinensis in winter contributed more to the total abundance than the other species in each season, with values 0.84,0.39, 0.91 and 0.63, respectively, they were the dominant species in the seasons above mentioned. Moreover, the contributions among various dominant species to total abundance of mysids were similar in winter and surmner whereas different in spring and autumn. It was found that the total abundance in spring and overall seasons showed significant linear correlation with bottom temperature, while the abundance show significant correlation with bottom salinity in summer and winter, and with surface and 10 m temperature in autumn. The variation of mysid abundance was linked with ebb and flow of runoff from continental rivers, especially affected by the Changjiang Dilute Water. The peak abundance in autumn also associated with the duration of warm current from summer to autunm. The oecurence of high abundance area of mysids in autumn plays an important role in forming of fishing ground for Scomberjaponicus and Decapterus manuadsi in the north offshore of the East China Sea and the Minnan-Taiwan bank.