珠江口附近海区甲壳类动物的区系特征及其分布状况

根据2006年8月（夏季）、2006年10月（秋季）、2006年12月（冬季）和2007年4月（春季）珠江口附近海区的底拖网调查资料，分析了该海域甲壳类动物的区系特征和分布状况.结果表明：本次调查共采获甲壳类动物54种，分隶于2目17科25属，其中，虾类22种、蟹类22种、虾蛄类10种；该海域甲壳类动物多数为热带 亚热带的暖水性种类，少数为广温性种类，未出现暖温性和冷温性种类；广盐性的种类最多，其次为高盐性种类，低盐性种类最少；大多数种类属于印度洋 西太平洋区系；调查海域的甲壳类动物种类与东海、菲律宾海、印度尼西亚海、日本海关系较密切，与黄海、渤海、朝鲜海关系较疏远.调查海域甲壳类动物的优势种为周氏新对虾、口虾蛄、武士蟳、红星梭子蟹、猛虾蛄、锈斑蟳、日本蟳、长叉口虾蛄、中华管鞭虾、三疣梭子蟹和逍遥馒头蟹.出现的种类数以秋季最多（33种），春季最少（26种）.甲壳类资源密度在水深0～40 m水域较高，在水深10～20 m最密集.调查海域甲壳类动物的平均资源密度为99.60 kg·km^-2，以夏季最高（198.93 kg·km^-2）、春季最低（42.35 kg·km^-2）；组成甲壳类动物的3个类群中，蟹类的资源密度最高（41.81 kg·km^-2），其次是虾类（38.91 kg·km^-2），虾蛄类最低（18.88 kg·km^-2）；各类群资源密度存在明显的季节变化，虾类在夏季最高（120.32 kg·km^-2）、春季最低（0.67 kg·km^-2），蟹类和虾蛄类则均在冬季最高（62.01和29.49 kg·km^-2）、秋季最低（24.64和6.30 kg·km^-2）.

Faunal characteristics and distribution pattern of crustaceans in the vicinity of Pearl River estuary

Based on the data of bottom trawl surveys in the vicinity of Pearl River estuary in August (summer), October (autumn), December (winter) 2006, and April (spring) 2007, the faunal characteristics and distribution pattern of crustaceans were analyzed. A total of 54 species belonging to 25 genera, 17 families, and 2 orders were collected, including 22 species of shrimps, 22 species of crabs, and 10 species of squills. Most of the crustaceans were tropical-subtropical warm-water species, a few of them were eurythermal species, and no warm-water and cold-water species occurred. Euryhaline species were most abundant, followed by halophile species, and the low-salinity species were the least. Most of the crustacean species belonged to the fauna of Indian Ocean-western Pacific Ocean. The faunal assemblages were closer to those of the East China Sea, Philippine Sea, Indonesia Sea, and the Japan Sea, and estranger with those of the Yellow Sea, Bohai Sea, and Korea Sea. The dominant species were Metapenaeus joyner, Oratosquilla oratoria, Charybdis miles, Portunus sanguinolentus, Harpiosquilla harpax, Charybdis feriatus, Charybdis japonica, Oratosquilla nepa, Solenocera crassicornis, Portunus trituberculatus, and Calappa philargius. The crustaceans had the largest species number (33) in autumn and the least one (26) in spring, and the highest stock density at the water depth of <40 m, especially at 10-20 m. The average stock density of the crustaceans was estimated to be 99.60 kg·km^-2, with the highest (198.93 kg·km^-2) in summer and the lowest (42.35 kg·km^-2) in spring. Of the 3 species groups, crabs had the highest stock density (41.81 kg·km^-2), followed by shrimps (38.91 kg·km^-2), and squills (18.88 kg·km^-2). The stock densities of the 3 species groups showed an obvious seasonal variation. Shrimps had the highest stock density (120.32 kg·km^-2) in summer and the lowest density (0
.67 kg·km^-2) in spring, while crabs and squills had the highest density (62.01 and 29.49 kg·km^-2, respectively) in winter and the lowest density (24.64 and 6.30 kg·km^-2, respectively) in autumn.