Pelagic Mysidacea in East China Sea and its significance as the indicator of water mass

Based on the investigation data of four seasonal oceanographic censuses in the area 23°30'-33°N and 118°30'-128°E of East China Sea in 1997-2000,this paper studied the ecotypes and geographic and seasonal distribution of pelagic Mysidacea in this sea area,with its significance as the indicator of water mass approached.The results showed that among the species of pelagic Mysidacea,Acanthomysis latiscauda,Gastrosaccus pelagicus,Siriella sinensis and Hemisiriella pulchra were the coastal subtropical species with some features of warm temperate species,while Pseudanchialina pusilla,Promysis orientalis,Erythrops minuta and Anisomysis bipartoculata were the offshore subtropical species with some features of tropical species.Different from other zooplanktons,most of the pelagic Mysidacea species had lower optimal temperature and salinity and distributed more at near-shore in spring and winter,showing the features of warm temperate near-shore species.The areas with high abundance of A.latiscauda,S.sinensis and H.pulchra were just the converging areas of the Changjiang dilute waters and warm current masses and of coastal waters and offshore high salinity waters.Erythrops minuta and Anisomysis bipartoculata could be used as the indicators of warm current,P.orientalis and Doxomysis quadrispinosa were the indicators of the Taiwan warm current,while the rest were not good enough to be the indicators of water masses.