COMMUNITY STRUCTURE OF SNAILS AND ITS RELATIONSHIP WITH ENVIRONMENTAL FACTORS ALONG ZHEJIANG COAST IN SPRING

Based on the survey data collected in April 2015 via bottom trawl along Zhejiang coast, this study identified the species composition and dominant species, as well as analysed the resource biomass and density, and community diversity. In addition, the relationship between the community structure of snails and environmental factors was also explored in this study. The results showed that 27 snail species were identified, and they belong to 2 orders, 15 families and 21 genera. The dominant species were Turritella bacillum and Siphonalia spadicea; The average biomass and density were 246.64 kg/km² and 27.75×10³ ind./km², respectively, whose distributions appeared to be inhomogeneous. However, the density in the northern area was lower than that in the middle-southern area. The average values for species abundance index (D), species diversity index (H′) and species evenness index (J′) were 0.36, 0.56 and 0.50, respectively, indicating the snail community diversity was on a low level. Species diversity index (H′) display spatial distribution pattern, but the other two indexes remained almost constant in the study area. The ABC curve showed that snail community was unstable in spring. According to the CCA analysis, the distribution of snail community was affected mainly by depth, bottom temperature and bottom dissolved oxygen in the surveyed area.