Status of macrobenthic diversity and distribution in Subei Shoal, China

Five cruise surveys were carried out in May–June 2013 to evaluate the status of macrobenthic diversity and distribution in Subei Shoal, China. Twenty-four stations were sampled and divided into four groups according to depth (5–10 m, 10–20 m, 20–30 m and 30–35 m). A total of 163 species were collected with Polychaeta dominating in species composition and abundance. All of the community parameters (abundance, biomass, mean species richness, Margalef richness index, Shannon-Wiener index and Pielou's evenness) were not significantly different among the five cruises or among the four groups, except that Shannon-Wiener index at 5–10 m was significantly lower than that in other depth groups. No significant difference in community structure was detected among cruises, but when the data from the same station were pooled together, significant differences among stations were observed basically from inshore to offshore. The benthic opportunistic polychaetes amphipods index showed four stations having moderate ecological status in Subei Shoal. Canonical correspondence analysis showed that Sigambra bassi and Praxillella sp. were positively correlated with depth and salinity, and Paralacydonia paradoxa was positively correlated with dissolved oxygen.