Weinrauch Alyssa M, Lazaro-Côté Analisa, Durhack Travis C, Enders Eva C, Jeffries Ken M
Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, Manitoba, Canada.
J Fish Biol. 2025 Jun 26. doi: 10.1111/jfb.70111.
Lake trout (Salvelinus namaycush) is an important food fish in northern communities, inhabiting cool, well-oxygenated water, but climate change is reducing available habitat, with extended summer stratification of lakes creating an upper thermal barrier (15°C) and lower dissolved oxygen (DO) boundary (4-7 mg L). Together, these environmental factors can influence tolerance thresholds and climate change may lead to abiotic factors exceeding these physiological thresholds in lake trout habitats. Thresholds can shift with environmental acclimation in lake trout populations, but the functional basis of this shift has yet to be examined. The abundance of transcripts offers insight into underlying cellular responses to environmental stressors that can provide an early warning of adverse physiological outcomes. Here, we used a stress-response transcriptional profiling chip to investigate a suite of genes involved in thermal and general stress in lake trout acclimated to a range of temperatures (6-18°C) and two DO conditions (10 or ~6 mg L), as well as following acute thermal stress (i.e. CT). Transcriptional profiles were assessed in the gill, liver and epidermal mucus. Generally, fish acclimated to the greatest combined stressor (i.e. 18°C and 6 mg L DO) had the largest transcriptional response, suggestive of a transition from a routine stress response to an extreme survival response. A noted temperature dependence occurred in liver tissue, which was not evident in gill or mucus tissues. Further, transcriptional responses in the gill and mucus were highly correlated (r = 0.74-0.87), highlighting the potential use of these tissues for non-lethal sampling methods to enhance management and conservation strategies for lake trout.
湖红点鲑（Salvelinus namaycush）是北方社区重要的食用鱼，栖息于凉爽、富氧的水域，但气候变化正在减少其可用栖息地，湖泊夏季分层延长导致形成上部热障（约15°C）和下部溶解氧（DO）边界（4 - 7毫克/升）。这些环境因素共同作用会影响耐受阈值，气候变化可能导致湖红点鲑栖息地的非生物因素超过这些生理阈值。湖红点鲑种群的阈值会随环境适应而变化，但其变化的功能基础尚未得到研究。转录本的丰度有助于深入了解细胞对环境应激源的潜在反应，这些反应可为不良生理结果提供早期预警。在此，我们使用应激反应转录谱芯片研究了一系列参与热应激和一般应激的基因，这些基因存在于适应一系列温度（6 - 18°C）和两种溶解氧条件（约10或约6毫克/升）的湖红点鲑中，以及急性热应激（即CT）之后。在鳃、肝脏和表皮黏液中评估转录谱。一般来说，适应最大综合应激源（即18°C和6毫克/升溶解氧）的鱼具有最大的转录反应，这表明从常规应激反应向极端生存反应的转变。肝脏组织中存在明显的温度依赖性，这在鳃或黏液组织中并不明显。此外，鳃和黏液中的转录反应高度相关（r = 0.74 - 0.87），突出了这些组织在非致死采样方法中的潜在用途，以加强湖红点鲑的管理和保护策略。
