黄海无脊椎动物资源结构及多样性

Structure and diversity of invertebrate resources in the Yellow Sea

根据1998～2000年在黄海进行的生物资源底拖网定点试捕调查,所取得的春、夏、秋、冬4季347个样方的无脊椎动物资料,分析了黄海无脊椎动物的资源结构及多样性。调查捕获无脊椎动物53种、2336 896kg、1385397尾。运用相对重要性指数(IRI)作为生态优势度的度量指标,依此来划定每个种在群落中的作用。IRI大于1000的种类定为优势种,全年只有1种,即冷温性的脊腹褐虾(Crangonaffinis),该种的渔获量占总渔获量的61 4%;IRI值在1000～100的种类定为重要种,有3种(类),即枪乌贼(Loligosp )、太平洋褶柔鱼(Todarodespacificus)和鹰爪虾(Trachypenaeuscurvirostris),它们的渔获量占总渔获量的25 8%。使用物种丰富度指数(D)、Shannon Wiener多样性指数(H′)和种类均匀性指数(J′)剖析了该水域无脊椎动物群落的多样性特征。群落各样方指数D=0 000～2 347,H′=0 000～2 140,J′=0 006～1 000。此外还采用Bray Curis指数CN来比较黄海不同区域无脊椎动物群落之间物种组成的相似性。研究结果表明,黄海北部无脊椎动物群落与黄海南部无脊椎动物群落之间的种类组成相似性最高,CN=0 846,黄海中部无脊椎动物群落与黄海南部无脊椎动物群落之间的种类组成相似性最低,CN=0 478。经分析,黄海现有无脊椎动物群落的优势种及多样性具有比较好的稳定性。

This study is based on the data of 347 samples from bottom trawl surveys in spring,summer,autumn and winter from 1998 to 2000.The surveys were carried out in the Yellow Sea outside the line of trawl ban zone by research vessel 'Bei Dou'.Fifty-three species of invertebrate,with a total catch of (2336.896kg),1385397individuals,were caught.The mean relative biomass of four seasons was (6.735kg/h),the mean relative density 3992ind/h,and the mean body weight 1.69g.Shrimps accounted for 72.7% by weight,squids for 20.8%,and crabs for 6.5%.Shrimps accounted for 95.2% by number of individuals,squids for 2.5%,and crabs for 2.3%.The mean relative biomass was the greatest in summer,and the smallest in spring.The mean relative density was the highest in autumn,and the lowest in spring.The mean individual weight was the heaviest in winter,and the lightest in autumn.The number of species caught was the most in winter,and the fewest in summer.The index of relative importance(IRI) is used in measuring ecological dominance of species to decide the role each species plays in the community.The species with index of relative importance(IRI) above 1000 is defined as the dominant species.Crangon affinis,the cold-temperate species,was all dominant species in four seasons,of which the catch accounted for 61.4% of the total catch in weight.The IRI value of Crangon affinis varied with seasons that the value (9910) was the highest in spring,and the lowest in winter (4989).Other dominant species was Todarodes pacificus(1646)in summer,and Loligo sp.(1291)in winter.The species with value of IRI between 100 and 1000 is taken as the major species.Only three major species,Loligo sp.,Todarodes pacificus and Trachypenaeus curvirostris,accounted for 25.8% of the total catch in weight.The species with value of IRI between 10 and 100 was taken as the common species,which were Charybdis bimaculata,Metapenaeopsis dalei,Palaemon gravieri and Sepioda birostrata,of which the weight accounted for 4.3% of this total catch.Other 44 species,which was taken as rare species with value of IRI below 10,accounted for 8.5% of the total catch in weight.Three diversity indexes,i.e.species abundance index(D),Shannon-Wiener diversity index(H′)and species evenness index(J′),were calculated to analyze the characteristics of species diversity of invertebrate communities.The value of D is 0.000-2.347,H′ 0.000-2.140,and J′ 0.006-1.000.The three diversity indexes varied with seasons.The average of index D (0.789) was the largest in spring,and the smallest in summer (0.307).The average of index H′(1.034) was the largest in winter,and the smallest in summer (0.333).The average of index J′(0.612) was the largest in winter,and the smallest in autumn(0.418).The seasonal change of variation coefficient of the three diversity indexes was obvious.The variation coefficients of indexes D and H′ were all the largest in summer,and the smallest in winter.The variation coefficients of index J′ was the largest in autumn and the smallest in winter.Similarity index (C(N)) is used to compare the similarity of species composition with areas communities.The similarity of species composition was the largest between the invertebrate communities of the north and the south of the Yellow Sea and the value of C(N) is 0.846.The similarity of species composition was the least between the invertebrate communities of the middle and the south of the Yellow Sea and the value of C(N) is 0.478.Present dominant species and diversity of invertebrate community in the Yellow Sea is due to a long term of adaptation between organisms and hydrographic environment,so that the community has been in good concert with the environment,and the dominant species of invertebrate community in the Yellow Sea has better stability.