Abstract:In order to track the fishery resources in Haizhou Bay, we conducted preliminary studies on the community structure of fishery resources in the northern area of Haizhou Bay. The data were collected in bottom trawl surveys in May 2012 (spring). In the survey totally 51 species were collected including 33 species of fish, 14 species of crustaceans and 4 species of cephalopods. The range of the biomass distributions of fishery resources was 13.55−35.90 kg/h, with an average of 24.59 kg/h. The range of the number distributions of fishery resources was 1858−14844 ind/h, with an average of 8046.58 ind/h. The individual density of fishery resources was 65.58×103−589.92×103 ind/km2, with an average of 297.24×103 ind/km2. The biomass density of fishery resources was 428.34−1420.16 kg/km2, with an average of 919.09 kg/km2. The dominant species were Syngnathus acus, Pholis fangi and Metapenaeopsis dalei. There were 15 important species including Callionymus kitaharae, Liparis tanakae, Lophius litulon, Heptacarpus rectirostris etc. The species richness (D), Shannon-Wiener diversity index (H′) and evenness index (J′) were calculated based on the survey data. D was 1.400−3.255, with an average of 2.471; H′ was 0.492−2.309, with an average of 1.857; J′ was 0.182−0.713, with an average of 0.596. The previous survey in 1980s showed that there were 150 species of fish in Haizhou Bay, therefore since then the diversity of fish species have greatly declined. The numbers of crustaceans and cephalopods species were also decreased compared to data (19 species of crustaceans and 6 species of cephalopods) from other researchers. The biomass and numbers of the main economical species were reduced. Small and low-value fish species and Metapenaeopsis dalei have gradually taken over the dominance. Tailfish (Trichiurus lepturus), an economical species, was not found. These phenomena may result from over-fishing and/or anthropogenic pollutions.
