Tuna Research and Conservation Center, Monterey Bay Aquarium, 886 Cannery Row, Monterey, CA, 93940, USA.
Hawaii Institute of Marine Biology, University of Hawaii at Manoa, PO Box 1346, Kaneohe, HI, 96744, USA.
Sci Rep. 2017 Sep 5;7(1):10434. doi: 10.1038/s41598-017-11059-6.
Salmon sharks Lamna ditropis are highly migratory, upper trophic level predators in North Pacific ecosystems. We analysed a multi-year satellite tag dataset to investigate the habitat use of female salmon sharks across their broad range in the eastern North Pacific (NEP) and identified key environmental factors that influence vertical distribution. Salmon sharks displayed remarkable plasticity in habitat use across disparate oceanographic regions in the NEP and increased utilization of deeper waters in offshore habitats. Diel shifts in vertical distribution and behaviour were consistently observed across their range and likely reflect shifts in their foraging ecology. Salmon sharks utilized a broad thermal niche and exhibited submergence behaviour, possibly for thermal refuge, when encountering sea surface temperatures outside their preferred temperature distribution. Moreover, the vertical distribution of salmon sharks indicates they were able to exploit low dissolved oxygen environments (<1-3 ml l), occasionally for extended periods of time in offshore habitats. However, salmon sharks generally reduced their use of deeper waters when encountering the combination of cold temperatures (<6 °C) and low dissolved oxygen concentrations (<1-3 ml l). Combining vertical distribution with high-resolution horizontal movements furthers our understanding of the ecological and environmental drivers of movement across short (diel) and long-term (migratory) scales.
大西洋长尾鲨是高度洄游的上层掠食者，分布于北太平洋生态系统。我们分析了多年的卫星标签数据集，以调查大西洋长尾鲨在北太平洋东部（NEP）广泛分布范围内的栖息地利用情况，并确定了影响垂直分布的关键环境因素。大西洋长尾鲨在 NEP 的不同海洋学区域表现出显著的栖息地利用可塑性，并增加了对近海栖息地深水区的利用。在整个分布范围内，昼夜垂直分布和行为的变化一直存在，这可能反映了它们觅食生态的变化。大西洋长尾鲨利用了广泛的温度生态位，并表现出潜水行为，当遇到超出其适宜温度分布范围的海面温度时，可能是为了寻找热避难所。此外，大西洋长尾鲨的垂直分布表明它们能够利用低溶解氧环境（<1-3 ml l），偶尔在近海栖息地长时间停留。然而，当遇到低温（<6°C）和低溶解氧浓度（<1-3 ml l）的组合时，大西洋长尾鲨通常会减少对深水区的利用。将垂直分布与高分辨率水平运动相结合，可以更深入地了解短时间（昼夜）和长时间（洄游）尺度上运动的生态和环境驱动因素。
