东海深海底层鱼类群落及其结构的研究

本文据东海深海1981年底鱼资源调查资料,按不同站、水深带之间计算渔获物组成的相似性指数C_2,应用聚类分析方法等综合分析,结果表明:调查海区底层鱼类可区分为东海大陆架(外缘)群落、东海大陆被群落和冲绳海槽(西侧)群落等三个(主)群落。其中,东海大陆坡群落还可细分为大陆坡上部、中部和下部等三个亚群落。同时,应用种类多样性、均匀性、丰盛度和优势度指数(H~1;D、J、d和D_2),对群落结构进行分析,结果表明:H~1、D、J或d值,一般是水深浅处较小,深处较大,它们随水深的变化趋势相似;D_2值则与以上各值大致相反。作者认为除种类组成和多样性指数外,种类相似性指数也是反映生物群落结构的一个重要特征。

A STUDY ON THE DEEP SEA DEMERSAL FISH COMMUNITIES AND THEIR STRUCTURES IN THE EAST CHINA SEA

The data are based on the survey of the deep sea demersal fishresources of the East China Sea (120--1055 m depth) during the period of May toNov., 1981. 101 captured species were selected from 53 sampling stations. Accordingto different sampling stations and varioss depth belts in the catch composition, theindex of species similarity O. was calculated and by using cluster analysis method thecommunity division was analyed. The results show that from shallow water to deepwater the demersal fish can be divided into three major communities in the surveyed area, i. e. the community of the outer region of the continental shelf at the depth of120-200m, the community of the continental slope at the depth of 200-950 m andthe community of Okinawa Trough at the depth of 950-1055m in the East ChinaSea. Among them the depths of the major transitive belt are near 150-200 m and900-950 m respectively. Futhermore, the community of continental slope can besubdivided into three minor communities, i. e. the upper part, the middle part andlower part of communities. The minor transitive belts are located at about 400 mand 700 m depth respectively, Meanwhile, by bottom topographic and hydrographiccharacteristics, the divided bounderies of the sea or water mass in the surveyed areaare basically in accordence with the location of the major transitive belts. Havingapplied the indices of the species diversity H'(Shannon-Weaver) and D (Simpson),the index of the species evenness J (Pielou), the index of species richness d (Marga-lef) and the index of the species dominance D₂ (McNaughton), the result of analysisof the community structure shows that the values of H, D, J, and d are lower at theshallow water, higher at the deep water and stable between them generally, they aresimilar to the tendency of the depth variation. While the value D₂ is contrary to theabove values roughly. Moveover, the authors realize that not only the species composi-tion and the index of diversity but also the index of species similarity are the impor-tant characteristics of the community structure.