Pacific salmonids, cold-water fishes native to the northern hemisphere, span a massive geographic range (~ 33° latitude) and are exposed to a wide variety of environmental conditions regionally and temporally. California is home to the greatest concentration of at-risk anadromous salmonids and warming river temperatures pose both current and future threats to numerous populations. Thermal standards for management of California populations are currently based on guidelines for multiple salmonid species and from populations across the Pacific Coast. However, a growing body of literature suggests that salmonid populations exhibit population-specific thermal requirements. Furthermore, in California, salmonid populations regularly encounter temperatures that exceed current thermal standards based upon performance of outside populations. This review focuses on Chinook salmon ( Oncorhynchus tshawytscha ), providing evidence for interpopulation variation in thermal performance across life stages, and explores the drivers of variation. To describe the formation of interpopulation variation, we define fundamental and ecological thermal physiologies. Fundamental thermal physiology is the composite of intrinsic physiological traits and abiotic factors that define a species’ thermal window. Ecological and environmental interactions constrain this fundamental thermal physiology, yielding an ecological thermal physiology. Thermal physiology, viewed through this lens, provides researchers and managers avenues for salmonid research and conservation at the population scale. A more nuanced approach to west-coast salmonid conservation will be required to protect the most at-risk and vulnerable populations. Successful salmonid management must incorporate population-specific traits and present and future watershed conditions.

中文翻译：

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一种尺寸并不适合所有人：太平洋鲑鱼的热生态生理变化

太平洋鲑鱼是北半球原生的冷水鱼类，跨越广阔的地理范围（约 33° 纬度），在区域和时间上暴露于各种环境条件。加利福尼亚州是面临风险的溯河鲑鱼最集中的家园，河流温度升高对众多种群构成当前和未来的威胁。加利福尼亚种群管理的热标准目前基于多种鲑鱼物种和整个太平洋沿岸种群的指导方针。然而，越来越多的文献表明鲑鱼种群表现出特定于种群的热需求。此外，在加利福尼亚州，鲑鱼种群经常遇到超过当前基于外部种群表现的热标准的温度。本综述重点关注奇努克鲑鱼 ( Oncorhynchus tshawytscha )，为不同生命阶段热性能的种群间变异提供证据，并探讨变异的驱动因素。为了描述种群间变异的形成，我们定义了基本和生态热生理学。基本热生理学是定义物种热窗口的内在生理特征和非生物因素的组合。生态和环境相互作用限制了这种基本的热生理学，产生了生态热生理学。从这个角度来看，热生理学为研究人员和管理人员提供了在种群规模上进行鲑鱼研究和保护的途径。需要采取更细致的方法来保护西海岸鲑鱼，以保护最危险和最脆弱的种群。成功的鲑鱼管理必须结合特定种群的特征以及当前和未来的流域条件。