长江口及邻近海域浮游端足类分布特征

Distribution characteristics of pelagic Amphipoda in the Changjiang Estuary and adjacent waters

根据2002—2003年长江口28°00′-32°00′N，122°00′-123°30′E海域4个季节的海洋调查数据，运用定量、定性方法探讨了长江口及邻近海域浮游端足类总丰度的平面分布、季节变化及与渔场的关系，分析了优势种的数量变动和对浮游端足类总丰度的贡献，并与东海外海种类的生态特征做了比较。结果表明，长江口及邻近海域浮游端足类丰度季节变化主要受温度的影响，而平面分布变化则与盐度相关。平均丰度在夏季最高（2.75个/m^3），在冬季最低（0.10个/m^3）。本次调查共发现浮游端足类49种，江湖独眼钩虾（Monoculodes limnophilus）和裂颏蛮（Lestrigonus schizogeneios）是最主要的优势种，江湖独眼钩虾在四季中对端足类总丰度都有很大贡献，在春秋冬三季为第一优势种，说明江湖独眼钩虾对相对较低的温度具有一定的适应能力，裂颏蛮则只在春夏秋季有较大贡献，其中夏季裂颏蛮贡献率为0.87，高于江湖独眼钩虾，这与裂颏蛮具有较高温度的环境适应能力有关。浮游端足类种类数与总丰度都与表层温度的线性相关显著，同表层盐度的相关不显著。作为长江口鱼类的重要饵料之一，浮游端足类的数量分布对长江口和舟山海域渔场的形成有重要的意义。

Seasonal oceanographic cruises were conducted in the waters of the Changjiang Estuary （28°00′-32°00′N and 122°00′-123°30′E） from 2002 to 2003. Based on the data from the investigation, the seasonal distribution and abundance of pelagic Amphipoda in the Changjiang Estuary were dicussed through aqualitative and quantitative method. The relationship of pelagic Amphipoda abundance with the fish ground, the abundance variation of dominant species and thier contribution to pelagic Amphipoda abundance were all considered. It was found that the seasonal Amphipoda abundance was influenced by the seasonal surface temperature. Moreover, the horizontal distribution of its abundance was influenced by the surface salinity in the waters of the estuary. The abundance was the highest （2.75ind./m^3） in summer and the lowest （0.10ind./m^3） in winter. Of the 49 species identified, Monoculodes limnophilus and Lestrigonus schizogeneios were the mostly dominant species. Monoculodes limnophilus was dominant species in four seasons; it was the main dominant specie in spring, summer and autumn affected by the characteristics relatively low temperature warm adaptation, compared with Lestrigonus schizogeneios who was dominant specie just in spring summer and autumn. The contribution of Lestrigonus schizogeneios to Amphipoda abundance was 0.87, higher than Monoculodes limnophilus in summer attributed to tropical water adaptation. There was a significant correlation between abundance and the surface temperature, and was no significant correlation with surface salinity. As an important diet of fish in the Changjiang Estuary, the Amphipoda distribution is important in the fishing ground there.