秋季南日岛西部海域游泳动物种类组成及其多样性

根据2011年秋季南日岛西部海域的底拖网调查资料，分析了该海域游泳动物种类组成、物种多样性和资源密度分布特征.结果表明，调查海域共出现游泳动物80种，隶属于18目51科63属.相对重要性指数（IRI）大于500的优势种类有鹿斑鲾（Leiognathus ruconius）、杜氏枪乌贼（Loligo duvaucelii）、叫姑鱼（Johnius grypotus）、口虾蛄（Oratosquilla oratoria）等7种；Shannon-Wiener物种多样性指数平均值为2.36，种类丰富度指数平均值为4.15，均匀度指数平均值为0.70.所有游泳动物质量相对资源平均密度为1116.23 kg/km2，尾数相对资源平均密度为108 215 ind/km2.该海域游泳动物资源密度处于中等水平，但资源的利用价值并不高，多数为小型种类.

Nekton Species Composition and Biodiversity in the Western Waters of Nanri Island in Autumn

Based on the data in the bottom trawl survey in Autumn,2011,the species composition,community diversity of nekton,and resource density distribution in the western waters of Nanri Island were studied.A total of 80 nektonic species were recorded,which belonged to 63 genera,51 families and 18 orders.There are 7 dominant species（IRI > 500）,such as Leiognathus ruconius,Oratosquilla oratoria,Loligo duvaucelii,Johnius belengerii and so on.The average Shannon-Wiener index（H′）is 2.36,species richness index was 2.36,evenness index was 4.15.The relative resource density of nekton quality is 1116.23 kg/km2,while the relative resource density of nekton quantity is 108 215 ind/km2.In this area,the resource density of nekton was in the medium level,but the utilization value of fishery resource was not high,and the most of the species were small nekton.