Relationship between spatial distribution of zooplankton and environmental factors in the Changjiang Estuary and its ad-jacent waters in spring

This study was carried out in the Changjiang Estuary and its adjacent waters from 15th to 23rd,April,2009.The aim was to examine the species composition,abundance and biomass,and the spatial distribution of the zooplankton community.The correlation between zooplankton and some influential factors were studied with mul-tivariate analysis based on the sample data and environmental parameters.A total of 81 taxa of the zooplankton in-cluding 9 pelagic larvae were identified.Calanus sinicus,Muggiaea atlantica and Sagitta nagae were the dominant species in the cruise.The zooplankton of the Changjiang Estuary and its adjacent waters could be divided into four groups: estuary brackish water species,neritic oligohaline species,euryhaline species and high-temperaturehyperhaline species.The average abundance of zooplankton was 100.1 ind /m3,and average biomass 154.1mg /m3.Compared with different subareas,both abundance and biomass were the highest in the Outside Estuary Subarea and the lowest in the Hangzhou Bay Subarea.The main factors that influenced the distribution of zooplankton in the survey area were salinity,temperature,and chla.