Ecological characters of zooplankton in middle area of Subei Shoal in spring and summer

Based on the zooplankton samples collected from the middle area of Subei Shoal(33°04′～33°12′,121°02′～121°12′) during May Aug 2009,the ecological characters of zooplankton in the area were studied,such as the quantity,dominant species and season changes.The result showed that the succession of dominant species in the two seasons was obvious.Labidocera euchaeta,Paracalanus parvus,L.sinilobata and Calanus sinicus were the primary dominant species in spring(May).L.euchaeta,Sagitta bedoti,Acartia pacifica were the primary species in summer(Aug.).The seasonal variations of dominant species were mainly determined by the change of temperature.In summer the species were decreased and the warm water species added.The average biomass of zooplankton was 1 091.23 mg/m3 in spring and 487.11 mg/m3 in summer.Moreover,the average abundance of zooplankton was 1 855.59 d/m3 in spring and 871.37 d/m3 in summer.According to the large quantity and high diversity of zooplankton in the studied area,in Subei Shoal,some fishes' spawning and nursing grounds provided the abundant food for the fish larvae and juveniles.