人工鱼巢生境中罗非鱼与土著鱼类的互作机制

The composition of fishery resource in the Pearl River has been modified remarkably with the explosion of tilapias and the attenuation of habitat diversityin the Pearl River. Tilapias have become the predominant in several regions, which produces a threat of losing a great deal of indigenous fishery resources and germplasm resources. In recent years，study on interspecific interactions between fish species by artificial structure habitat has been widely used in fishery resources and biodiversity conservation. In the past, the study on the effects of Tilapia on native fish were based on the analysis of catch in the river, but the interaction mechanism between tilapia and native fish is shown unclearly in artificial structure habitat. This project is based on the artificial structure habitat as the carrier, and the combination of resource science of fish, ichthyological ecology, hydroacoustics, behavioristics of fish and underwater photography will be implemented to probe into the unclear interaction mechanism between tilapia and native fish. In this project, we will analyse the relationship between tilapia and native fish in the food web, the community dynamics and the behavior of tilapia and native fish to clarify the interspecific interaction mechanism in the artificial structure habitat. The study will play a significant role in the resource conservation of indigenous fishery and fish diversity in the Pearl River, and provide the key technologies for the construction of artificial structure habitat.

外来物种罗非鱼在珠江出现，加上流域生境的湖泊化、片段化等造成的江河生境多样性衰减，改变了以土著鱼类为主的江河渔业资源的结构，罗非鱼已成为珠江的优势种。这一生态效应持续扩大，将导致珠江土著鱼类资源严重匮乏及种质资源丧失。近年来，通过人工生境研究鱼类种间互作已广泛应用于鱼类资源养护和多样性恢复中。以往罗非鱼对土著鱼类影响的研究，是基于江河生境衰减条件下的渔获物分析得出。其结果不尽说明人工构建的鱼巢小生境中罗非鱼与土著鱼类种间互作效应。本项目以人工鱼巢生境为载体，将鱼类资源学、鱼类生态学、水声学等技术方法结合，研究罗非鱼与土著鱼类在人工鱼巢生境中食物链（网）、时空分布差异及行为和对鱼类多样性影响的三个方面种间互作效应。弄清两者在人工鱼巢生境中的食物链（网）关系和鱼类数量时空动态变化特征；分析实验区与对照区的鱼类多样性差异，揭示罗非鱼对鱼类群落多样性影响等。阐明人工鱼巢生境中两者的种间互作机制。

通过长期持续监测研究，从人工生境对鱼类的聚集效果、饵料效应、产卵场效果和庇护作用评估人工生境对鱼类资源修复和养护效果，探究罗非鱼和土著鱼类种间互作机制。以期为内陆水域鱼类多样性的保护和资源养护提供依据。人工生境区浮游动植物种类数、密度、生物量以及生物多样性均高于对照区。人工生境能提高鱼类丰度、多样性和鱼类种类数。人工生境鱼类平均丰度显著高于对照区（p<0.01），分别为37.35尾和19.83尾，人工生境鱼类丰度是对照区鱼类丰度的1.88倍。鱼类生态类型分析结果表明，人工生境以口端位、中上层、杂食性鱼类为主，且所占比例与对照区相比均有增加。鱼类群落结构相似性分析结果显示，鱼类群落结构在时间上和生境之间 存在显著性差异。群落结构稳定性分析结果显示，人工生境鱼类群落结构在整体上基本稳定未受到干扰；对照区群落结构极不稳定，受到严重干扰。 实验室模拟实验结果显示人工生境可以帮助仔鱼抵御捕食者追击，提高仔鱼存活率。当人工生境不存在时，罗非鱼或银鮈仔鱼单独与捕食者革胡子鲇处于同一水族箱时，革胡子鲇会在2小时内将仔鱼全部捕食。当人工生境存在时能够显著提高仔鱼存活率。