我国鲑科鱼类的温度适应性研究：生理功能与生态表现

In the context of global climate warming, the fitness and evolution process of species would be affected. The physiological plasticity is critical important for determining the ultimate fate of a given species in a changing environment. The thermal adaptive evolution of the Salmonidae fishes, a very important group of cold-water fish, has been of particular interest to world scientists. Both the geographical distribution (from cold temperate zone to subtropics) and the habitat environment of the Salmonidae fishes in China are very special. Notably, some areas represent the southernmost distribution of Salmonid fish worldwide. Therefore, the family Salmonidae in China is an perfect ideal biological group to study the thermal adaptive evolution of fish, and to predict the ecological effects of climate warming. This project plans to systematically carry out the comparative physiology of the taxa to conventional temperature acclimation and the stress ecology of the taxa to the extreme temperature changes in summer and winter, based on our previous national fund project. The physiological responses (including aerobic metabolism, swimming performance, metabolic mode, etc.) and ecological performances (including body size, foraging and anti-predator behavior, the ability to cope with thermal shock, etc.) of different species will be investigated through different ways of temperature acclimation and simulated warming. Moreover, the trade-offs between thermal adaptation, energy countermeasures and ecological performances in the Salmonidae fishes will be examined as well. The planed project will not only help to reveal the thermal adaptive evolution of cold-water fish, and to predict the ecological effects of climate warming, but also provide the necessary theoretical basis for the aquaculture and ecological protection of the Salmonidae fishes in China.

在全球气候变暖的背景下，物种的适合度与进化进程受到影响，生理可塑性大小将决定其在变动环境中的最终命运。鲑科鱼类作为冷水性鱼类的重要类群，其温度适应性进化备受科学界关注。我国鲑科鱼类地理分布环境特殊且差距巨大（从寒温带至亚热带均有分布），是研究冷水性鱼类温度适应性进化以及预测气候变暖生态效应最为理想的生物类群。本课题拟在前期项目研究工作的基础上，系统开展我国鲑科鱼类的温度适应性比较研究以及该类群应对气候变暖致夏季和冬季极端温度变化的胁迫生态学研究。通过温度驯化和模拟升温分别考察不同物种的生理响应（有氧代谢与运动能力、代谢模式等）与生态表现（个体大小、捕食与反捕食能力、应对热冲击能力等），并探讨鱼类温度适应与能量对策及其生态表现的权衡。相关研究不仅有助于揭示冷水性鱼类的温度适应性进化、预测气候变暖的生态效应，而且可为我国鲑科鱼类的养殖与生态保护提供必要的理论基础。

我国鲑科鱼类地理分布环境特殊且差距巨大（从寒温带至亚热带均有分布），是研究冷水性鱼类温度适应性进化以及预测气候变暖生态效应最为理想的生物类群之一。本课题较为系统地开展了我国几种鲑科鱼类（秦岭细鳞鲑Brachymystax lenok tsinlingensis、细鳞鲑Brachymystax lenok、太门哲罗鲑Hucho taimen、马苏大麻哈鱼Oncorhynchus masou、花羔红点鲑Salvelinus malma）的保护生理与生态适应研究，比较了不同物种的代谢模式与热生理学特征，构建了我国鲑科鱼类系统发育树，探讨了鱼类温度适应性与其遗传特性和地理分布模式的关联，揭示了气候变暖可能对其生理功能和生态表现的影响；在理论上，提出了“暖冬致山溪鱼类能量赤字关联的化学通讯功能弱化进而引起种群衰退假说”、“环境依赖的鱼类代谢可重复性假说”、“鱼类化学通讯的生态位假说”等理论假设并进行了系列实验验证，从不同的生态学视角剖析了鱼类表型进化与环境响应。研究发现，不同气候域和相同气候域分布的几种鲑科鱼类在形态适应、生理功能和生态表现方面均存在差异，但这种差异化的表型适应与其气候域分布特点并不吻合，提示以上几种鲑科鱼类的热适应性能较为保守，推测未来气候变化将对鲑科鱼类种群及其所处的水域生态系统造成多方面的负面影响。相关研究丰富了鱼类温度适应与保护生态学理论，有助于预测气候变暖的生态效应，为我国鲑科鱼类的生态养殖与保护实践提供了十分必要的理论基础。