南沙群岛西南陆架海域主要底层经济鱼类的食性

对多齿蛇鲻（Ｓａｕｒｉｄａｔｕｍｂｉｌ）、蓝圆（Ｄｅｃａｐｔｅｒｕｓｍａｒｕａｄｓｉ）、深水金线鱼（Ｎｅｍｉｐｔｅｒｕｓｂａｔｈｙｂｉｕｓ）和短尾大眼鲷（Ｐｒｉａｃａｎｔｈｕｓｍａｃｒａｃａｎｔｈｕｓ）４种经济鱼类优势种群进行食性分析，根据其胃含物中饵料生物的重量组成和出现频率，可分为３种食性类型。多齿蛇鲻以摄食小型鱼类为主，兼食底栖生物；短尾大眼鲷和蓝圆以摄食浮游动物和小型鱼类（包括幼鱼）为主，兼食底栖生物；深水金线鱼以摄食底栖生物和小型鱼类为主，兼食浮游动物的食性类型。还分析了４种鱼类的食物关系和营养级。

Food habits of main economic fishes on the continental shelf along the southwest sea off Nansha Islands

The food habits of 4 dominant economic fish populations, Saurida tumbil, Decapterus maruadsi, Nemipterus bathybius and WTBX]Priacanthus macracanthus were analysed.Based on the weight composition of food organsims in their stomachs and appearing freguencies, 3 kinds of food habits may be distinguished: Saurida tumbil mainly feeds on small fishes and benthos; Decapterus maruadsi and Priacanthus macracanthus mainly feed on zooplanktons,small species (including young fishes)and benthos as well; Nemipterus bathybius mainly feeds on benthos,small species and zooplanktons as well.The 3 kinds of food habits represent most demersal fishes along the continental shelf off Nansha Islands. The relationships of food habits among the 4 species are analysed. The nutrient levels of N.bathybius,P.macracantlus and D. maruadsi range from 2.1 to 3.4,averaged 2.8,2.6,2.7,respectively. They all belong in lower carnivorous animal,mainly feeding on herbivorous animals and omnivorous animals. S.tumbi Z]belong in medium carnivorous animal,mainly feeding on lower carnivorous animals and its nutrient level averaged 3.4.