Abstract: Four voyage investigations were conducted in the Jiaozhou Bay from 2016 to 2017 to study community structure (species composition, density, and biomass) of macrozoobenthos, seasonal variation of diversity index and its relationship with environmental factors. A total of 117 species were collected, of which 56 species were annelins, 31 arthropods, 14 molluscs, 6 echinoderms, 6 chordata, and 4 other groups. There were 66 macrozoobenthos species in the winter investigation, compared to 47, 44, and 30 species in the spring, autumn, and summer, respectively. The total density of macrozoobenthos was the greatest in the winter followed by spring, autumn, and then summer. Total biomass was the greatest in the spring followed by in the winter, autumn, and summer. Heteromastus filiformis was the dominant species in the spring, autumn, and winter. Shannon index and Margalef richness index were significantly negatively correlated with temperature and inorganic nitrogen levels (P<0.05), while Pielou evenness index was not significantly correlated with any environmental factors (P>0.05). The results of Canonical Correspondence Analysis (CCA) based on population density showed that temperature, organic matter, and median organism size were the main factors affecting the distribution of macrozoobenthos. According to the environmental requirements of macrobenthos, most species distributed in low temperature, low nutrient content and shallow water area with small grain size.

Key words: Jiaozhou Bay, macrozoobenthos, community structure, environmental factor.