Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 49, Hobart, TAS, 7001, Australia.
Sci Rep. 2017 Jul 3;7(1):4545. doi: 10.1038/s41598-017-04806-2.
Understanding how aquatic species respond to extremes of DO and temperature is crucial for determining how they will be affected by climate change, which is predicted to increasingly expose them to levels beyond their optima. In this study we used novel animal-borne DO, temperature and depth sensors to determine the effect of extremes of DO and temperature on the vertical habitat use of Atlantic salmon Salmo salar in aquaculture cages. Salmon showed a preference for temperatures around 16.5 to 17.5 °C, however, selection of preferred temperatures was trumped by active avoidance of low DO (<35% saturation) at the bottom of the cage. In addition to low DO, salmon also avoided warm surface waters (>20.1 °C), which led to a considerable contraction in the available vertical habitat. Despite their avoidance behavior, fish spent a large amount of time in waters with suboptimal DO (<60% saturation). These results show that vertical habitat contraction could likely be a significant consequence of climate change if the reduction in DO outpaces the increase in hypoxia tolerance through local adaptation. They furthermore highlight that site-specific environmental conditions and stock-specific tolerance thresholds may need to be considered when determining stocking densities.
了解水生物种对 DO 和温度极值的反应对于确定它们将如何受到气候变化的影响至关重要，气候变化预计将使它们越来越多地暴露在超出其最适范围的水平。在这项研究中，我们使用了新型的动物携带 DO、温度和深度传感器，以确定 DO 和温度极值对水产养殖笼中大西洋鲑 Salmo salar 垂直栖息地利用的影响。鲑鱼对 16.5 到 17.5°C 左右的温度表现出偏好，但对底部低 DO（<35%饱和度）的主动回避优先于对优选温度的选择。除了低 DO 之外，鲑鱼还避免温暖的表层水（>20.1°C），这导致可利用的垂直栖息地大大收缩。尽管鲑鱼有回避行为，但它们在 DO 低于 60%饱和度的水中花费了大量时间。这些结果表明，如果由于局部适应导致 DO 减少超过缺氧耐受能力的增加，那么垂直栖息地收缩可能是气候变化的一个重大后果。此外，它们还强调，在确定放养密度时，可能需要考虑特定地点的环境条件和特定种群的耐受阈值。
