人工鱼礁区食物网结构和功能对季节性低氧的响应-以烟台牟平人工鱼礁区为例

Artificial reefs has being widely constructed in China, forming a typical ecosystem mainly dominated by reef fishes and other attaching organism. With global climate change and human activities, marine hypoxia occurred in some artificial reef areas in China, which caused severe damage to the ecological environment and aquaculture industry. Response of structure and function of artificial reef food web to seasonal hypoxia is needed to study, for the purpose of providing theoretical and data to maintain the stability, development and function of artificial reef ecosystem. This project intends to focus on the artificial reef area with seasonal hypoxia, and study the response of the reef fish population and community structure, and diurnal distribution. Through stomach analysis and stable isotope analysis, diet composition and trophic level of reef fish will be determined, then analysis the influence of seasonal hypoxia on the feeding preferences, competition and trophic niche of reef fishes. Based on the historical and measured data, Ecopath model was constructed to quantitatively evaluate the effect of seasonal hypoxia on the energy flow and stability of the artificial reef ecosystem. This project provides the decision support based on the ecological system for the management of artificial reef area which is under the influence of seasonal hypoxia, and provides theoretical and data reference for ecological effect evaluation of seasonal hypoxia.

人工鱼礁建设已在我国广泛开展，形成了以岩礁鱼类为主要捕食者的典型生态系统。伴随着气候变化和人类活动加剧，部分人工鱼礁海域发生了严重的海洋低氧现象，导致近海渔业生产活动遭受重创。系统地研究季节性低氧影响下人工鱼礁食物网结构和功能的响应机制，将为人工鱼礁生态系统的稳定、健康发育以及生态服务功能的持续实现提供科学保障。本项目拟选择发生季节性低氧的人工鱼礁海域，查明人工鱼礁区岩礁鱼类的群落结构和昼夜分布对季节性低氧的响应规律；通过胃含物分析和稳定同位素技术，测定岩礁鱼类的食物组成和营养级，分析季节性低氧影响下岩礁鱼类的摄食偏好、食性竞争和生态位的响应规律；结合历史资料和实测数据，构建Ecopath模型，定量评估季节性低氧对人工鱼礁生态系统能流特征和稳定性的影响。研究结果将为低氧灾害影响下人工鱼礁海域的管理提供决策支持，也可为低氧灾害生态效应的评估提供理论和数据参考。

海洋缺氧对海洋生物群落及食物网结构和功能的影响受到广泛关注，夏季季节性低氧对人工鱼礁食物网结构和功能的影响研究，是保障人工鱼礁生态系统健康发育的重要内容。通过对烟台近岸不同生境条件下的渔业群落结构监测，结果表明底层渔业生物CPUE、优势种及群落多样性指数存在明显的区域差异和季节变动，其中水深、溶氧和温度对底层渔业群落结构影响显著。对两种岩礁生境下许氏平鲉和大泷六线鱼的胃含物分析结果表明人工鱼礁区夏季空胃率较高，许氏平鲉夏季空胃率达到90%。利用碳氮稳定同位素技术对两种鱼类食物来源及生态位重叠进行分析，结果表明两种鱼类的生态位重叠度在自然岩礁区显著高于人工鱼礁区，秋季生态位重叠度最高，冬季生态位重叠度最低。通过构建两种岩礁生境食物网Ecopath模型，比较了不同生境条件下食物网能流特征，结果表明人工鱼礁区与自然岩礁区的系统总流量TST分别为每年6455.47和9490.48t/km2，总初级生产力TPP/总呼吸量TR分别为1.93和1.49。以上结果为近海缺氧对渔业食物网影响评估提供基础，为人工鱼礁及海洋牧场生态安全保障及策略制定提供支撑。