The rise in temperature associated with climate change may threaten the persistence of stenothermal organisms with limited capacities for beneficial thermal acclimation. We investigated the capacity for within-generation and transgenerational thermal responses in brook trout (Salvelinus fontinalis), a cold-adapted salmonid. Adult fish were acclimated to temperatures within (10°C) and above (21°C) their thermal optimum for 6 mo before spawning, then mated in a full factorial breeding design to produce offspring from cold- and warm-acclimated parents and bidirectional crosses between parents from both temperature treatments. Offspring from families were subdivided and reared at two acclimation temperatures representing their current (15°C) and anticipated future (19°C) habitat temperatures. Offspring thermal physiology was measured as the rate of oxygen consumption (Mo₂) during an acute change in temperature (increase of 2°C h⁻¹) to observe their Mo₂-temperature relationship. We recorded resting Mo₂, peak (highest achieved, thermally induced) Mo₂, and critical thermal maximum (CTM) as performance metrics. Although limited, within-generation plasticity was greater than transgenerational plasticity, with offspring warm acclimation elevating CTM by 0.5°C but slightly lowering peak thermally induced Mo₂. Transgenerational plasticity was evident as a slightly elevated resting Mo₂ and a shift of the Mo₂-temperature relationship to higher rates overall in offspring from warm-acclimated parents. Furthermore, offspring whose parents were warm acclimated were in worse condition than those whose parents were cold acclimated. Both parents contributed to offspring thermal responses; however, the paternal effect was stronger. Despite the existence of within-generation and transgenerational plasticity in brook trout, it is unlikely that these will be sufficient for coping with long-term changes to environmental temperatures.

中文翻译：

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温带鲑鱼响应热驯化和急性温度应力的代内和跨代可塑性

与气候变化相关的温度升高可能会威胁到热适应能力有限的狭窄热生物的持续存在。我们研究了溪鳟 ( Salvelinus fontinalis ) 的代内和跨代热反应能力)，一种适应寒冷的鲑鱼。成鱼在产卵前 6 个月在 (10°C) 和高于 (21°C) 的最佳温度范围内适应温度，然后在全因子育种设计中进行交配，以从冷温驯化的亲本和双向杂交中产生后代来自两种温度治疗的父母之间。来自家庭的后代被细分并在代表其当前（15°C）和预期未来（19°C）栖息地温度的两个适应温度下饲养。后代热生理被测量为在温度急剧变化（增加 2°C h ^-1 ）期间的耗氧率（M o ₂ ），以观察它们的 M o ₂ -温度关系。我们记录了休息 M o ₂、峰值（达到的最高、热诱导）M o ₂和临界热最大值 (CTM) 作为性能指标。虽然有限，但代内可塑性大于跨代可塑性，后代温暖适应使 CTM 升高 0.5°C，但略微降低热诱导的 M o ₂峰值。跨代可塑性明显表现为静息 M o ₂略微升高和 M o _2移动-温度与温暖适应的父母后代的总体发病率较高的关系。此外，父母温驯的后代比父母冷驯的后代状况更差。父母双方都对后代的热反应做出了贡献；然而，父系效应更强。尽管鳟鱼存在代内和跨代可塑性，但这些可塑性不足以应对环境温度的长期变化。