Dressler Terra L, Anlauf-Dunn Kara, Chandler Andrea, Eliason Erika J
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
Stillwater Sciences, 996 S. Seaward Ave, Suite 102, Ventura, CA 93001, USA.
Conserv Physiol. 2025 May 1;13(1):coaf030. doi: 10.1093/conphys/coaf030. eCollection 2025.
Salmonid fishes are a focal point of conservation physiology due to their high value to humans and ecosystems, and their susceptibility to decline from climate change. A significant challenge in conserving these fishes is that populations of the same species can be locally adapted to vastly different habitats within their wild ranges and can therefore have unique tolerance or vulnerability to environmental stressors within those habitats. Within the state of Oregon, USA, summer steelhead () inhabit both cool, coastal waters most typically associated with Pacific salmonids and arid, inland environments where temperatures are more extreme. Here, we utilized streamside physiological experiments paired with habitat temperature monitoring to assess the thermal tolerance and vulnerability of four populations of summer steelhead from distinct thermal habitats. All populations had unique responses of critical thermal maximum, aerobic scope and exercise recovery to temperature. Despite populations from warm habitats exhibiting higher thermal tolerance than populations from cooler habitats, summer steelhead from warm habitats appear to be more vulnerable to the physiological consequences of warming based on the extreme temperatures they already experience during the summer. These results demonstrate an example of thermal physiology varying between populations within the same portion of their latitudinal range and highlight the need for habitat-specific conservation strategies for this species.
鲑科鱼类因其对人类和生态系统具有重要价值，且易受气候变化影响而数量减少，成为保护生理学的重点研究对象。保护这些鱼类面临的一个重大挑战是，同一物种的种群可能在其野生分布范围内局部适应截然不同的栖息地，因此对这些栖息地内的环境压力源具有独特的耐受性或脆弱性。在美国俄勒冈州，夏季虹鳟（）栖息于凉爽的沿海水域，这类水域通常与太平洋鲑科鱼类相关，也栖息于干旱的内陆环境，那里的温度更为极端。在此，我们利用溪边生理实验并结合栖息地温度监测，来评估来自不同热栖息地的四个夏季虹鳟种群的热耐受性和脆弱性。所有种群对临界热最大值、有氧代谢范围和运动恢复的温度反应都各不相同。尽管来自温暖栖息地的种群比来自凉爽栖息地的种群表现出更高的热耐受性，但基于它们在夏季已经经历的极端温度，来自温暖栖息地的夏季虹鳟似乎更容易受到变暖的生理影响。这些结果展示了在同一纬度范围内的不同种群之间热生理学存在差异的一个例子，并突出了针对该物种制定特定栖息地保护策略的必要性。
