Abstract:

In order to analyze the species composition and evaluate the stability of nekton community structure in Sandu Bay of Fujian Province, species diversity, an Abundance Biomass Comparison (ABC) curve and taxonomic diversity were described based on a net fishing survey conducted in Sandu Bay from October 2012 to September 2013. A total of 195 species belonging to 125 genera, 64 families and 17 orders were recorded including 143 fish species, 47 crustacean species and 5 cephalopod species. Larimichthys crocea was the most dominant species identified in all four surveys and most were escaped groups from fish farms. The other dominant species included Johnius belengerii, Argyrosomus argentatus, gobies, and several crustacean species, which were characteristized by small body size, short breeding period and seasonal or annual drastic fluctuations in biomass. The average Shannon-Wiener diversity index in Sandu Bay was 2.61, and higher in September and October than in January and May. ABC curve analysis showed that the community structure had obvious seasonal changes and the impacting factors may include internal factors and external factors such as the supplement of breeding groups, individual growth, fishery production, and summer fishing moratoriums. This study revealed that the biomass proportion of the large yellow croaker has a very significant negative correlation with Shannon-Wiener diversity index (P < 0.01, R = -0.890) and a significant negative correlation with species number (P < 0.05, R = -0.563). Combined with survey data from recent years, there were 224 fish species in Sandu Bay; based on this data, the average taxonomic distinctness (△⁺) and the variation in taxonomic distinctness (∧⁺) were tested. The result showed that the value of △⁺ in Sandu Bay was 59.5 and the value of ∧⁺ was 260.8. Compared with other coastal waters in China, the average taxonomic range in Sandu Bay was relatively narrow and the taxonomic status was extremely uneven, indicating the anti-interference ability of the fish community in Sandu Bay was poor.

Key words: ABC curve, biodiversity, taxonomic diversity, Sandu Bay