[Species characteristics and diversity of pelagic Mysidacea in East China Sea].

Based on the investigation data of four oceanographic cruises in the East China Sea (23 degrees 30' - 33 degrees 00' N, 118 degrees 30' - 128 degrees 00') in 1997-2000, this paper studied the species characteristics and diversity of mysids, and the relationships between its species number and environmental factors. A total of 18 mysids species were observed, with 14 species occurred in autumn, 9 species occurred in summer, 7 species occurred in spring, and 4 species occurred in winter. The species composition showed a clear seasonal alternation, especially from autumn to winter. Seawater salinity was the main environmental factor affecting the distribution of the mysids. In summer and winter, mysids distribution was mainly affected by the runoff from continental rivers, and species number had a significant negative correlation with seawater salinity, while in autumn, the species number had a negative correlation with surface seawater temperature but a positive correlation with bottom seawater salinity. The spatial-temporal variation of mysids geographical distribution was linked with the ebb and flow of the Changjiang River, and the dominant species of mysids tended to agglomerate, which was the major reason of the low diversity of mysids in the East China Sea.