Variation of community structure of Cephalopods in spring and autumn along the coast of Zhejiang Province

Coast of Zhejiang Province is one of the important fishery production areas in China. As an important part of the marine ecosystem, Cephalopods also play a very important role in the coastal fisheries of Zhejiang Province. Based on the trawl survey data along the coast of East China Sea in spring and autumn during 2014-2016, all the Cephalopods species were selected, and we analyzed the species and dominant species composition using statistical methods, studied the spatial-temporal distribution of the dominant species, and also investigated the dynamics of community structure using the ecological methods. The results showed that a total of 22 species were captured and identified in the three-year survey, which belonged to 3 orders, 7 families and 10 genera, dominant species were Abralia multihamata, Loliolus beka, Uroteuthis duvauceli, Uroteuthis edulis, Sepiola birostrata and Octopus minor. Spatial and temporal variations of cephalopod community were presented. Octopus minor dominated in the north station in spring, and its biomass density was higher at the south station, and Uroteuthis edulis, Abralia multihamata and Loliolus beka were the dominant species in autumn, and the biomass density in 2016 is much lower than two years before. Cluster analysis separated two groups based on different years, months and stations, and significant difference existed among community structures. Octopus minor made the largest contribution to the communities, and also made a decisive effect on the spatial community structure, migration may be the main factor for the seasonal dynamic of community structures.