Abstract:Based on the samples collected from the four cruises carried out in November 2012, February, May and August 2013, the species composition, abundance and distribution of zooplankton along the coast of Chang Island in the Bohai Sea were studied. The results showed that a total of 38 species (genera) of zooplankton were identified. There were 26 and 23 zooplankton species (genera) in summer and autumn, respectively, which were significantly higher than those in spring and winter. Variations in the dominant zooplankton species composition occurred obviously between different seasons. The dominant species were Centropages mcmurrichi and Calanus sinicus in spring, but replaced completely by Sagitta crassa, Ophiopluteus larva and Mysidaeea larva in summer. Sagitta crassa was the only dominant species in autumn. In addition to Sagitta crassa, Centropages mcmurrichi and Calanus sinicus dominated the zooplankton community in winter. The abundance of zooplankton varied significantly between different seasons. The average abundance of zooplankton was 1 952.74 ind/m3 in spring, which was significantly higher than those in other seasons. And the average abundance of zooplankton was 352.51 ind/m3, 87.38 ind/m3 and 79.95 ind/m3 in summer, autumn and winter, respectively. The Shannon-Wiener index (H) ranged from 0.222 to 2.766 during the sampling period and the average H value was 1.190. Pielou evenness index (J) varied from 0.121 to 0.940 with an average of 0.444 during the study period. The most important environmental factors influencing the changes of zooplankton species composition, abundance and distribution were water temperature, salinity, phytoplankton abundance and hydrological conditions along the Coast of Chang Island in the Bohai Sea.