Department of Forest Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4.
J Exp Biol. 2011 Sep 15;214(Pt 18):3074-81. doi: 10.1242/jeb.060517.
Little is known of the physiological mechanisms underlying the effects of climate change on animals, yet it is clear that some species appear more resilient than others. As pink salmon (Oncorhynchus gorbuscha) in British Columbia, Canada, have flourished in the current era of climate warming in contrast to other Pacific salmonids in the same watershed, this study investigated whether the continuing success of pink salmon may be linked with exceptional cardiorespiratory adaptations and thermal tolerance of adult fish during their spawning migration. Sex-specific differences existed in minimum and maximum oxygen consumption rates (M(O2,min) and M(O2,max), respectively) across the temperature range of 8 to 28°C, reflected in a higher aerobic scope (M(O2,max)-M(O2,min)) for males. Nevertheless, the aerobic scope of both sexes was optimal at 21°C (T(opt)) and was elevated across the entire temperature range in comparison with other Pacific salmonids. As T(opt) for aerobic scope of this pink salmon population is higher than in other Pacific salmonids, and historic river temperature data reveal that this population rarely encounters temperatures exceeding T(opt), these findings offer a physiological explanation for the continuing success of this species throughout the current climate-warming period. Despite this, declining cardiac output was evident above 17°C, and maximum attainable swimming speed was impaired above ∼23°C, suggesting negative implications under prolonged thermal exposure. While forecasted summer river temperatures over the next century are likely to negatively impact all Pacific salmonids, we suggest that the cardiorespiratory capacity of pink salmon may confer a selective advantage over other species.
对于气候变化对动物影响的生理机制知之甚少，但很明显，有些物种比其他物种更具弹性。在加拿大不列颠哥伦比亚省，粉鲑（Oncorhynchus gorbuscha）在当前气候变暖的时代蓬勃发展，与同一流域的其他太平洋鲑鱼形成鲜明对比，本研究调查了粉鲑的持续成功是否可能与其成年鱼类在产卵洄游期间的异常心肺适应和耐热性有关。在 8 到 28°C 的温度范围内，两性之间的最小和最大耗氧量（M(O2,min)和 M(O2,max)）存在性别特异性差异，反映出雄性的有氧范围（M(O2,max)-M(O2,min))更高。然而，两性的有氧范围在 21°C（T(opt)）最佳，并且与其他太平洋鲑鱼相比，在整个温度范围内都升高了。由于这种粉鲑种群的有氧范围的 T(opt)高于其他太平洋鲑鱼，并且历史河流温度数据显示该种群很少遇到超过 T(opt)的温度，这些发现为该物种在当前气候变暖期间持续成功提供了生理解释。尽管如此，在 17°C 以上，心输出量明显下降，在 23°C 以上，最大可达到的游泳速度受损，表明在长时间的热暴露下存在负面影响。虽然下一个世纪夏季河流温度的预测可能会对所有太平洋鲑鱼产生负面影响，但我们认为粉鲑的心肺能力可能赋予其相对于其他物种的选择性优势。
