特大型河口沿岸鱼类群聚格局及其维持机制研究

As one of the essential fish habitat, the coastal waters of large estuary play an important role in maintaining health of estuarine ecosystem and fishery resources. As the third largest river in the world,the Changjiang Delta is one of the most important estuaries in China with fishery ecological service functions. However, a lot of docks built in the riverbank of the Changjiang estuary, the habitat of the coastal waters emerged serious fragmentation, which has made the Changjiang Delta to lose the fishery ecological functions gradually. Therefore, in order to evalute the ecological impact of the habitat fragmentation, it is necessary to understand the fish assemblage of the coastal waters and its maintenance mechanism.In this project, the coastal waters of the Jingjiang section, located near the mouth of the Changjiang River estuarine, is selected as the experimental area. Fish samples collected in the past 12 years, as well as the samples collected in the next four years will be utilized. The project plans to use metacommunity theory mainly to investigate the distribution pattern of the coastal fish assemblage and to understand its structure and function in the time dimension using various of tools, such as biological diversity measure,functional group analysis,multivariate statistical analysis,stable isotope analysis,construction and comparison of simplify the food web. The ecological linkage of fish assemblage between the coastal and open water waters in the horizontal dimension will be clarified in this project as well. Based on the above efforts, the ecological maintenance mechanism of coastal fish assemblage pattern will be revealed. We trust that the results of this project can provide a theoretical basis for fishery resources and ecological protection in the large estuarine and its coastal waters.

大型入海河口的沿岸水域是鱼类关键生境之一，在维持健康的河口生态及渔业资源上具有重要作用。长江口是我国渔业生态服务功能最重要的河口之一。但长江河口码头林立，沿岸水域生境已出现严重的片段化，渔业生态功能正在逐步丧失，亟需了解沿岸水域鱼类群聚的结构特点及其维持机制。本项目以长江近口段目前岸线保存较完整的靖江河段作为实验区域，利用多年采集的丰富鱼类样本和环境资料以及今后4年的精心样本采集，依据近年发展起来的集合群落等现代生态学理论，采用生物多样性测度、功能群分析、多元统计分析、稳定同位素分析与简化食物网构建与比对等研究方法，在时间维度上分析沿岸鱼类群聚结构与功能的分布格局，在空间维度上阐明鱼类群聚在沿岸与敞水水域之间的生态联系。本项目有望揭示长江口沿岸鱼类群聚的时间分布格局及其生态维持机制，为特大型河口水产资源的保护提供生态学依据。

大型河口的沿岸水域是鱼类关键生境之一，在维持健康的河口生态和渔业资源上具有重要作用。长江口是我国渔业生态服务功能最重要的河口之一，但码头林立，沿岸水域生境已出现严重的片段化，亟需了解沿岸水域鱼类群聚的结构特点及其维持机制。.本项目以长江近口段目前岸线保存较完整的靖江河段作为实验区域，采集了鱼类群聚分析样本180份、约26500尾；稳定同位素分析样本1485号；主要优势种鱼类样本刀鲚400余尾、凤鲚7600余尾、成体鳗鲡208尾、鳗苗2585尾、弹涂鱼类350尾。逐尾分析鉴定了2003-2017年间采集的鱼类样本162140尾，测定了相关的生物学特征。测定了碳氮稳定同位素样本1200多份，刀鲚嗅觉基因转录组6个样本、嗅觉蛋白2个样本。主要结果如下。.①分析了长江靖江沿岸鱼类群聚的物种组成、物种组成的时间格局、物种组成的相似性、IRI指数的时间变化以及多样性指数的时间变化，阐明了长江近口段鱼类群聚组成及其多样性的时间格局。.②通过对鲇形目、鲌亚科、鮈亚科鱼类，以及鳜、胭脂鱼、刀鲚等名贵珍稀鱼类的生物量组成、单位努力捕捞量(CPUEN)时间变化、IRI指数时间变化的分析，以及贝氏䱗渔获量ARIMA预测模型的构建，基本弄清了几个优势类群的群聚格局及其关键性生态因子。.③通过大样本的各类生态样本碳、氮稳定同位素测定和模型分析，构建了长江口和钱塘江口的鱼类食物网结构。通过长江口鱼类食物网结构在枯水期与丰水期、沿岸水体与敞水水体的差异性比较，阐明了不同季节、不同水体鱼类营养级水平和食物组成的变化特征。.④通过对贝氏䱗（上层鱼类）、刀鲚和鳊（中层鱼类）以及似鳊（下层鱼类）等几个代表性物种在沿岸与敞水之间的食物来源差异性和生态位重叠度的比较，弄清了优势种在沿岸和敞水带的迁移状况，初步阐明了沿岸鱼类群聚的维持机制。.⑤另外，对刀鲚和日本鳗鲡的种质和资源生态作了研究分析，为长江口渔业资源的管理提供了基础的科学数据。