东海、黄海秋季渔业生物群落结构及其平均营养级变化特征初步分析

A preliminary analysis of variation characteristics of structure and average trophic level of the main fishery species caught by paired bottom trawl in the East China Sea and the Yellow Sea during the fall season

为了探讨东海、黄海渔业生物群落结构长期、连续的变化特征,采取聚类和平均营养级的分析方法研究了连续14年的底拖网秋季调查数据,对该海域主要渔业生物结构的变化阶段和规律进行了归纳与分析,将主要的渔业生物进行了类群划分,并分析了渔业生物群落平均营养级与资源密度之间的关系。结果表明,研究时间范围内渔业生物群落结构的发展分为3个阶段:水母暴发前期(1999—2003年),水母暴发期(2004—2007年)和水母暴发后期(2008—2012年)。暴发前期,资源量波峰与波谷变化周期为2年,后期则变为1年。水母暴发后,经过5年的剧烈波动发展,群落结构变化恢复到接近暴发前状态的趋势。此外,研究的主要渔业生物品种可以划分为暴发(沙海蜇)、优势(带鱼和小黄鱼)、异常(竹筴鱼)、常见(刺鲳、银鲳和黄鲫)、水母伴随(白色霞水母和海月水母)和偶见(日本鲭、龙头鱼等)6个物种类群。另据物种资源量在水母暴发前后的发生水平,偶见类群中的物种又可分为前期高后期低(龙头鱼、多棘腔吻鳕等)、前期低后期高(蓝点马鲛、大管鞭虾等)和没有变化(日本鲭)3个小类群,这些小类群中的物种具备了作为生态系统健康状态指示种的特征。最后,14年的渔业生物群落平均营养级与总资源密度对数呈极显著负相关(P<0.001),具体关系式为TL=-0.896 5·ln(CPUE)+14.142 1(TL为平均营养级,CPUE为单位捕捞努力量渔获量),此结果显示在营养级降低的同时会伴随整体资源量的增加,反之亦然。

To understand the long and consecutive variation characteristics of fishery species structure in the East China Sea and the Yellow Sea,using the method of clustering and average trophic level analysis,stages and features of main fishery species structure variation have been summed up and analyzed,and the main fishery species have been classified into groups,and the relation betw een average trophic level and fishery resources density has been analyzed,based on 14-consecutive-year fishery resources survey data in autumn from 1999 to 2012 by paired bottom traw l. The results show that the development of fishery species structure could be divided into 3 stages,including the early stage of jellyfish bloom（ 1999—2003）,the outbreak stage of jellyfish bloom（ 2004—2007） and the later stage of jellyfish bloom（ 2008—2012）. In the early stage,variation period of fishery resources is 2 years; but in the later stage the period changed to 1 year. With 5years of development after jellyfish bloom,it seemed that fishery species structure recovered to a stage close to the early stage of jellyfish bloom. By clustering method the main fishery species could be classified into 6species groups,including blooming（ e. g. Stomolophus meleagris）,advantage（ e. g. Trichiurus japonicus and Pseudosciaena polyactis）,unusual（ e. g. Trachurus japonicus）,common（ e. g. Psenopsis anomala,Pampus argenteus and Setipinna taty）,jellyfish accompanying（ e. g. Cyanea nozakii and Aurelia aurita） and rare（ e.g. Scomber japonicus,Harpadon nehereus etc.） species groups. By comparing quantities of species before and after jellyfish bloom,the species of rare species group could be classified into 3 groups： one with species whose quantity changed from high to low（ e. g. Harpadon nehereus,Coelorhynchus multispinulosus etc.）,one changed from low to high（ e. g. Scomberomorus niphonius,Solenocera melantho etc.） and the other w ith no change（ e. g. Scomber japonicus）,who in these groups had some characters of indicator species for ecosystem health state. Based on the data of 14 years,the relation betw een average trophic level and fishery resources density was significantly negative（ P 0. 001）,whose equation was TL =- 0. 896 5·ln（ CPUE）＋ 14. 142 1（ TL means average trophic level,CPUE means catch per unit effort）. The relation show s that the average trophic level of the marine ecosystem decreases with the increase of its total resources quantity,and vice versa.