Species composition and quantitative distribution of fishes in the Qitou Sea,Zhoushan

Based on the demersal fishes that collected by bottom trawl in the Qitou Sea belong to Zhoushan Fishing Ground in May and October 2012, we analyzed fish species composition, fauna characters, and quantitative distribution in the survey area, and the result showed: (1) 50 species of fish were found and identified in spring and autumn, which belonged to 11 orders and 28 families. More species belonged to Sciaenidae and Gobiidae, and each has 7 species, accounting for 14.0 %. (2) In thermal adaptation, fishes in this area could be divided into two types, including warm-water species, warm-temperate species. The fishes which were caught mainly belonged to warm-temperate species, who had 36 species, accounting for 72.0 %. (3) Distribution of the catch rates showed that more fishes were caught between the zone of Zhoushan Island to Xiaogan Island sea area in spring; and in autumn the fishes were concentrated on two sea area including Zhoushan Island to Xiaogan Island sea area, and the northwestern of Chuanshan Peninsula to Liuheng Island sea area. (4) There were 5 dominant species in spring that were Amblychaeturichthys hexanema, Trichiurus haumela, Lateolabrax japonicus, Collichthys lucidus, Harpodon nehereus; but in autumn, Harpodon nehereus was the unique dominant specie. (5) Considering the salinity and the water temperature of the area surveyed in bottom, the population structure of the dominant species was analyzed. The result showed that there was probably a feeding ground to the adolescent fish such as Trichiurus haumela, Lateolabrax japonicus and Collichthys lucidus in spring.