东山湾及其邻近海域游泳动物多样性的分析

DIVERSITY OF NEKTON IN DONGSHAN BAY AND ADJACENT AREAS

根据2009年11月至2010年8月在东山湾及其邻近海域的调查资料,统计渔获物物种组成,计算该海域各物种的相对重要性指数(IRI)、相对资源密度、Margalef种类丰富度指数、Shannon-Weiner种类多样性指数以及Pielou均匀度指数,并分析其时空分布特征。结果表明,东山湾及其邻近海域的物种组成比例与台湾海峡大体一致。秋冬春夏4个季度优势种种类数均较少,分别为4、2、1、3种,且季节更替明显。不同季节多样性指数表现为夏季>春季>秋季>冬季,各季Margalef种类丰富度均值为3.54,Shannon-Weiner种类多样性均值为1.99,Pielou均匀度均值为0.71;各调查站位Margalef种类丰富度均值为7.87,Shannon-Weiner种类多样性均值为2.94,Pielou均匀度均值为0.75,表明该海域生物多样性处于较低水平。分析东山湾及其邻近海域游泳动物多样性,可为今后开展海洋工程建设渔业资源损益评价、生态环境修复工作和基于生态系统的渔业和海洋管理策略提供科学依据。

The analyses of diversity of nekton in Dongshan Bay and adjacent areas were carried out based on the data of bottom surveys from November 2009 to August 2010. A systematic analysis of the nekton species composition was studied, and the index of relative importance （IRI）, relative resource density, Margalef richness index, Shannon-Weiner diversity index and Pielou evenness index were employed to assess the diversity of nekton. Also the spatial-temporal pattern of the nekton species in this area was described. The results showed that there were a total of 168 species involving 20 orders, 74 families and 109 genera in Dongshan Bay and adjacent areas. There were 114 fish species which was the largest category, accounting for 67.86%, and the results were shown the same trend compared with that of Taiwan Strait. In term of seasonal distribution, the most abundant of species was in spring （95） and least in autumn （66）; in term of the spatial distribution, the survey station 9 in summer had the largest number of nekton species （37）, while the survey station 3 had the least number （5） in the spring. The relative resource densities of spring and autumn were the higher, with winter the lowest and summer moderate. Dominant species had relatively less number of species, no more than four species, the number of dominant species in spring, summer, autumn and winter was 4, 2, 1 and 3 respectively. Dominant species were quite different and there was an obvious seasonal fluctuation. The level of diversity index indicated summer 〉 spring 〉 autumn 〉 winter. In term of the seasonal distribution, the average values of Margalef richness index, Shannon-Weiner diversity index and Pielou evenness index were 3.54, 1.99 and 0.71 respectively. In term of the spatial distribution, the average values of Margalef richness index, Shannon-Weiner diversity index and Pielou evenness index were 7.87, 2.94 and 0.75 respectively. Biodiversity of nekton in the area was at a low level, which was mainly due to over-fishing, water pollution and other comprehensive factors. This study could provide a scientific basis for marine construction, evaluation of fishery resources, marine ecological restoration, ecosystem-based fisheries and marine management strategy.