东海北部鱼类群落多样性和结构特征变化研究

IOCAS-IR > 海洋环流与波动重点实验室

	东海北部鱼类群落多样性和结构特征变化研究
其他题名	Variations in fish community structure and biodiversity in the northern East China Sea
	姜亚洲
学位类型	博士
	2008-06-06
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	东海北部鱼类群落生物多样性同功能种团长度谱 Abc曲线多元分析
摘要	在海洋渔业资源不断衰退的今天，渔业资源管理正经历着由单种和多种资源管理向生态系统水平管理的转变。开展在各种干扰因素影响下鱼类群落演替方向的研究是引入基于生态系统渔业管理策略的必要环节，本文以东海北部海域鱼类群落为研究对象，对其近十几年来结构和功能的变化趋势进行分析，以期今后为渔业资源的科学管理提供理论基础。捕捞是引起鱼类群落结构变化的最为重要的因素，本研究首先就捕捞对鱼类群落影响的国内外研究方法进行了综述与归纳。在研究捕捞对鱼类群落的影响时，所选用的群落参数指标应符合预期性、可测性、敏感性和排他性标准，业已利用的研究方法大致可为生物多样性、聚合特征指标、群落功能性指标、多元分析以及生态系统模型五大类。各研究方法单独使用均无法全面反映群落的结构变化状况，建议在实际研究过程中同时使用多种研究方法进行鱼类群落结构的变化分析，以期全面掌握捕捞活动影响下鱼类群落结构的变动状况，更好地为渔业资源的科学管理提供理论支撑。根据1991年1月和2004～2006年1月东海北部水域渔业资源底拖网调查资料，从物种和同功能种团两个层面分析了东海北部鱼类群落多样性及其结构组成特征的变化。同功能种团是生态系统中起着相似生态作用、并占据相近或相似生态位的若干物种集合体，本文结合各鱼种的摄食习性和活动能力差异，将该水域内的鱼类划分为8个同功能种团，分别为浮游动物食性种团、浮游/底栖动物食性种团、底栖动物食性种团、底栖/游泳动物食性种团、杂食性种团、活动能力强的游泳动物食性种团、软骨鱼类种团、活动能力弱的游泳动物食性种团。研究结果显示：东海北部冬季鱼类群落的物种多样性和同功能种团多样性呈显著线性正相关。经过十余年后，尽管该群落的物种多样性和同功能种团多样性均未发生显著变化，但各同功能种团内的物种数发生了明显变化，物种多样性与同功能种团多样性之间的关系曲线斜率由0.547增加到0.627，群落的生态冗余性有所降低。相似性分析检验表明，两时段群落间的物种和同功能种团结构组成均发生了显著变化，带鱼、龙头鱼、小黄鱼、黄鲫、灰鲳等物种和软骨鱼类种团、浮游/底栖动物食性种团相对量的变化是造成鱼类群落结构变化的主要因素。鱼类群落结构已显现出向以浮游动物食性和活动能力强的游泳动物食性鱼种为主体的方向发展的趋势。最后本研究对实施伏季休渔以后近十年来东海北部鱼类群落的动态进行了分析。研究表明：实施伏休以后部分物种得到一定程度的恢复，而另些物种在伏休结束后强大的捕捞压力下仍然不断衰退，群落的物种生物量组成正朝一定的方向进行变化，但是这种变化并没有给鱼类群落带来稳定性和功能性方面的好转，群落仍处于中度干扰状态，物种多样性没有得到显著提高；群落的生产力水平以及营养传递效率没有恢复的迹象。每年伏休结束后强大的捕捞压力使伏季休渔没有达到预期的效果。为更有效的保护渔业资源、恢复东海北部生态系统，建议继续加大管理力度，进一步降低该海域的捕捞强度。
其他摘要	Fisheries science and management are progressively switching their attention from single species to ecosystems, increasing the need for measuring the structure and functioning changes of fish community. In the study, we detect the changes of structure and biodiversity of fish community in the northern East China Sea during the recent decades. And we expected that the study could provide scientific basis for the theory and practice of fishery resources management. The graduation thesis consists of three chapters as follows: Since negative ecological impacts caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change, in the chapter I, the methods for evaluating the fishing effects on fish are reviewed. Previous studies showed that community descriptors might be used as indicators of the impact of fishing. The criteria used for the evaluation of these indicators are meaning, expected effect of fishing, exclusiveness to fishing effects, and measurability. Ecologists have developed five main classes of community metrics for such tasks: diversity, aggregate indicator, indicators based on communities’ functions, multivariate analyses and metrics derived from ecosystem models. Each class is explained briefly. Most of methods are sensitive to specific aspects of structural change in a community and each has particular advantages and disadvantages. No one measure is adequate to capture all community properties that may be interest, so it’s better use a suite of community metrics to explore a comprehensive view of community structural changes. Based on the data collected from bottom trawl surveys conducted in January of 1991 and 2004-2006, the temporal changes of fish community structure in the northern East China Sea in winter were analyzed in the chapter II. The changes were described in two taxonomic levels: one is in species level; the other is in functional group level. A total of eight functional groups were identified within this system, which are based upon trophic levels and adult mobility. They are planktivores, planktivores/benthivores, benthivores, benthivores/piscivores, omnivores, mobile piscivores, elasmobranch, roving piscivores, respectively. The results indicated that there was a significant and positive relationship between species and functional diversity. Species and functional diversity undergone little significant changes through more than ten years, while the slope of the linear model explained the relationship between species and functional diversity became steeper from 0.547 to 0.627 and the average number of species within most functional group became smaller except planktivores and benthivores. All these indicated that the level of redundancy of the fish assemble in the northern East China Sea was lower. Multivariate analyses indicated that there were significant changes in both species and functional group composition for the fish assemblage between the different periods. The chief discriminating species were Trichiurus japonicus, Harpadon nehereus ,Pseudosciaena polyactis , Setipinna taty and Pampus cinereus, while elasmobranch and planktivores/ benthivores were the main discriminating functional groups. The percentage of the total catch for planktivores/ benthivores, benthivores, benthivores/piscivores, omnivores, elasmobranch and roving piscivores decreased significantly in 2004-2006 compared to that in 1991, while the percentage of the total catch for the two other functional groups obviously increased. In summary, the fish community in the north of the East China Sea underwent the structural and functional changes during the recent decade. To protect the fishery resources effectively in the area, some measures must be implanted as follows: releasing the fishing pressure and reducing the environment pollution caused by human activities. The midsummer fishing moratorium system practiced annually by China government aims to protect the fishery resource and restore the marine ecosystem. To evaluate the effects of the measure on fish community, temporal changes in the structure and function of the fish community in the northern East China Sea were examined based on data from bottom trawl surveys in spring over the period 2000-2007 in the chapter III. The results revealed that some stocks such as small yellow croaker Pseudosciaena polyactis, Anglerfish Lophius Litulon, grey goblinfish Minous monodactylus restored following the implantation of the fishing moratorium system, while some other stocks, including butterfish Pampus argenteus, firefly-fish Acropoma japonicum, decreased. All of these should account to the directional changes of the fish community in term of the relative biomass composition. Although the relative species composition undergone directional changes, the fish community was still moderately disturbed. None of kinds of species diversity indexes(H', J', N1, N2) exhibited consistent changes during the study period, meanwhile the indictors related to function of fish community, including the slopes and intercepts of size spectrum, showed no consistent temporal variations, which reflected the productivity and turnover rate of the study community didn’t restore in the recent decade. The midsummer moratorium system didn’t play an obviously positive role in restoration of ecosystem in the study area. To maintain the ecosystem health, a comprehensive set of restrictions must be imposed on the fishery in the area.
页数	79
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/483
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	姜亚洲. 东海北部鱼类群落多样性和结构特征变化研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
10001_20052800683715（1392KB）			限制开放	--	浏览