Species composition and resource density of crustaceans in the continental shelf of northern South China Sea

Based on the data of four seasonal surveys in the continental shelf of northern South China Sea during 2006 to 2007,the species composition and resource density of crustaceans were analyzed.The results showed that there were 99 species belonging to 46 genera,22 families,2 orders in the area,and there were 32 species of shrimp,51 species of crab,16 species of squill.Most of them were tropical and subtropical warm water species,and they belonged to Fauna of India-western Pacific Ocean.The dominant species were Oratosquilla oratoria,Oratosquilla kempi,Portunus sanguinolentus,Charybdis feriatus,Portunus argentatus,Calappa philargius,Harpiosquilla harpax,Metapenaeopsis palmensis,Charybdis miles,Charybdis hongkongensis,Oratosquilla nepa.The catch rate distributed most with transect B(7.94 kg/h) and least with transect C(4.94 kg/h),it also showed obviously seasonal variation,most in autumn(10.31 kg/h) and least in winter(4.05 kg/h).The average catch rate was 6.54 kg/h;the catch rate of shrimps was 0.88kg/h and contributed 13.46% of crustaceans catch,the catch rate of crabs was 3.68 kg/h and contributed 56.27% of crustaceans catch,the catch rate of squills was 1.98 kg/h and contributed 30.27% of crustaceans catch.Crustaceans are distributed more in the area of 10m to 60m and most in the area of 10m to 20m of water depth.The resource density of crustaceans was 87.20 kg/km2,its resource density was most in autumn(137.47 kg/km2) and least in winter(54.00 kg/km2).