南海北部陆架区蟹类的种类组成和数量分布

Species composition and quantitative distribution of crabs in the northern continental shelf of South China Sea

根据2006--2007年南海北部陆架区4个季节的调查资料，分析了该海区蟹类的种类组成和数量分布状况。结果表明：南海北部陆架区共有蟹类51种，隶属于10科24属，以热带暖水性种类为主，属于印度洋一西太平洋区系中的南中国一东南亚海区；这些蟹类可分为3个生态类群——高温广盐生态类群、广温广盐生态类群和高温高盐生态类群；依据Pinkas判定，优势种为银光梭子蟹、红星梭子蟹、锈斑蝎、香港婚、逍遥馒头蟹、武士蜉、直额蟳、威迪梭子蟹；优势种类渔获率（2．99kg／h）占蟹类总渔获率（3．66kg／h）的81．69％；经济蟹类为红星梭子蟹、锈斑蜉、武士蝎、三疣梭子蟹、日本蝇、拥剑梭子蟹、远海梭子蟹，均属梭子蟹科种类，经济种类渔获率（2．37kg／h）占蟹类总渔获率（3．66kg／h）的64．75％；蟹类资源密度为97．47kg／km^2，经济蟹类资源密度为63．20kg／km^2。蟹类资源密度区域分布以D断面最高（125．60kg／km^2），C断面最低（70．93kg／km^2）；蟹类资源密度季节分布以秋季最高（181．60kg／km2），冬季最低（50．13kg／km^2）。蟹类密集区为10-60m深水域，尤以10m深附近水域分布最多，达222．13kg／km。，其数量分布趋势大致与水深呈负相关。

The species composition and distribution status of crabs were evaluated based on the data of four seasonal fishery resources surveys in the northern continental shelf of South China Sea from 2006 to 2007. The results showed that there were 51 species belonging to 10 families and 24 genera in the area, most of which were tropical warm - water species belonging to South China - Southeast Asia subregion of Indian - western Pacific fauna. Depending on their adaptability, all crab species were categorized into three ecological groups： tropical euryhaline group, eurythermic euryhaline group, and tropical halophile group, with predominant tropical euryhaline species including Portunus argentatus , P. sanguinolentus , P. tweediei , Charybdis feriatus , Charybdis hongkongensis , Calappa philargius,and Charybdis miles, C. truncata, by Pinkas. The catching rate of the predominant species （2.99 kg/h） was around 81.69% in total catching rate of crab species（3.66 kg/h）. The economic crab species Portunus sanguinolentus , P. trituberculatus , P. haanii, P. pelagicus , Charybdis feriatus , C. miles, and C. japonica belonging to Portunidae（2.37 kg/h） had the catching rate of around 64.75% of total catch rate （3.66 kg/h）. The crabs were stocked at a density of 97.47 kg/km2, including the economic crabs at stocking density of 63.20 kg/km2. The maximal distribution area of the crabs were found in the transect D （ 125.60 kg/km2） and the minimal in the transect C（70.93 kg/km2）. The maximal biomass of the crabs were observed in autumn（ 181.60 kg/km2） and the minimal in winter（50.13 kg/km2）. The most aggregation of crabs species were mainly distributed in depths of 10 -60 m with the peak （222.13 kg/km2） in depth of near 10 m, negative relation with the water depths.