[Characteristics of crustaceans community structure and its relationship with environmental factors in Dachenyang...

To elucidate the characteristics of fishery resources structure in the Dachenyang Spaw-ning Ground Reserve, the index of relative importance (IRI), biodiversity index and canonical correspondence analysis (CCA) were used to explore the relationship between crustaceans community and marine environment based on the bottom trawl survey data collected from April and November in 2018. A total of 38 crustaceans species were recorded, belonged to 25 genera in 14 families. The dominant species were Oratosquilla oratoria, Portunus trituberculatus, Charybdis bimaculata, and Parapenaeopsis hardwickii. The resource density of crustaceans was generally high in depths below 50 m in spring and in depths above 50 m in autumn. The density in the southern area was higher than nouthern area. The Margalef species richness index (D), Shannon diversity index (H) and Pielou evenness index (J) of crustaceans in spring was higher than that in autumn. The H of crustaceans in depths above 50 m was the highest. Based on cluster analysis and non-matrix multidimentional scaling analysis, the crustaceans could be classified into three groups in spring and four groups in autumn. The differences in crustacean community structure in spring were more significant than in autumn. The results of canonical correspondence analysis (CCA) showed that water depth, bottom temperature, salinity and dissolved oxygen were the main environmental factors affecting species composition and spatial structure of crustaceans in the surveyed area.