Abstract:Based on the data of four seasons fishery resources investigations in the continental shelf of northern South China Sea from 2006 to 2007, the composition and distribution of Squilla species were analyzed. The results showed there were 15 species belonging to 4 families and 7 genuses in the area. Based on their adaptability habitats, all species of Squilla were categorized into three ecological groups: tropical group, tropical semitropical group and eurythermic group, and most of them belonged to tropical semitropical group. The dominant species were Oratosquilla oratoria, O. kempi，Harpiosquilla harpax，O. nepa and H. raphideaccording to Pinkas IRI deternination. These species belonged to Squillidae and Harpiosquillidae, and their catch rate (1.86 kg/h) was around 98.17% of total catch rate (1.90 kg/h). The economic Squilla species were O. oratoria, O. kempi, H. harpax, O. nepa and O. ornata, which also belonged to Squillidae and Harpiosquillidae, and their catch rate (1.84 kg/h) was around 96.85% of total catch rate (1.90 kg/h). The average biomass of Squilla species was 42.18 kg/km2, while the average biomass of economic Squilla was 40.85 kg/km2.The temporal distributions of Squilla showed a highest biomass in transect B (76.27 kg/km2)and a lowest biomass in transect A (25.13 kg/km2); while the seasonal distribution of Squilla biomass showed a highest value in the autumn (49.24 kg/km2) and a lowest value in the winter (32.29 kg/km2). The distribution trends of Squilla biomass showed an approximately negative correlation with water depths, and they were mostly found at depths of 10~40 m and the highest value (173.40 kg/km2)was found at a depth of around 10 m; all species of Squilla belonged to economic species in the water area at about 10 m depth.
