Community structure of nekton in the waters around Dongtou Island in Autumn of 2019

Resource distribution characteristics of nekton in estuarine waters are related to hydrology, ecological environment changes and anthropogenic factors. A total of 49 species of nekton was found from 10 sites in the estuarine waters around Dongtou Island (DTI), with which the species of fish were in the highest proportion, followed by shrimp and crab. Average nekton biomass and abundance were 522.61 kg/km² and 28.60×10³ ind./km², significantly higher than that of previous studies. The distribution pattern was highest in the eastern part of DTI, lower in the ORE area, and lowest in the northern part of DTI. The intersection of water currents was an important hydrological factor in forming the high resource density area of nekton. Changes in the number of nekton were driven by the contribution of the two economically valuable dominant species of fish Harpodon nehereus and crab Portunus trituberculatus. The mean value of H' of nekton abundance was higher than that of nekton biomass. The species diversity of nekton in the sea near DTI was relatively low and community structure was in a relatively unstable state. The impact of human development activities on the nekton resources cannot be ignored, further research is essential.