Riding the tide: use of a moving tidal-stream habitat by harbour porpoises
Riding the tide: use of a moving tidal-stream habitat by harbour porpoises
复制标题
DOI：
10.3354/meps11677
复制
发表时间：
2016-05-10
影响因子：
2.5
通讯作者：
Wilson, Ben
中科院分区：
文献类型：
--
作者：
Benjamins, Steven;Dale, Andrew;Wilson, Ben
潮汐流栖息地呈现周期性的快速流动，湍流的条件。有证据表明，这些条件有利于顶级掠食者，如港口鼠海豚Phocoena phocoena，大概使他们能够优化猎物资源的开发。然而，这种关系的明确证明是复杂的事实，强大的潮汐流往往几乎同时发生在一个广泛的地区。大竞赛的海湾Corryvreckan（苏格兰西部，英国）是一个喷射潮汐系统，高能量的条件下，坚持在一个广泛的潮汐阶段在一个局部的，移动的补丁水。因此，海豚可以主动进入或避免这个栖息地，促进他们使用相邻的高和低能量环境的研究。使用被动声学海豚探测器（C-PODs）部署在静态系泊（类似于35天）和拉格朗日漂流物随电流自由移动（最多类似于48小时）的港口海豚的分布进行了研究。这种双重方法提供了互补的观点海豚的存在。停泊在伟大种族路径上的C-POD在能量潮汐射流通过期间的探测显着增加。漂流的C-POD记录的遭遇持续时间比停泊的C-POD记录的时间长，这表明鼠海豚倾向于随着水流向下游移动，而不是相对于海床保持静止或向上游移动。伟大种族充满活力、动荡的条件显然对海豚有吸引力，它们会随着时间的推移追踪其运动;然而，它们响应不断变化的潮汐情况的结构化运动不能简单地表示为当前速度和海豚存在之间的直接关系。
Tidal-stream habitats present periodically fast-flowing, turbulent conditions. Evidence suggests that these conditions benefit top predators such as harbour porpoises Phocoena phocoena, presumably allowing them to optimise exploitation of prey resources. However, clear demonstration of this relationship is complicated by the fact that strong tidal flows often occur near-simultaneously across a wide area. The Great Race of the Gulf of Corryvreckan (western Scotland, UK) is a jetting tidal system where high-energy conditions persist across a broad range of tidal phases in a localised, moving patch of water. Porpoises can therefore actively enter or avoid this habitat, facilitating study of their usage of adjacent high-and low-energy environments. The distribution of harbour porpoises was studied using passive acoustic porpoise detectors (C-PODs) deployed on static moorings (similar to 35 d) and on Lagrangian drifters moving freely with the current (up to similar to 48 h). This dual approach provided complementary perspectives on porpoise presence. C-PODs moored in the path of the Great Race registered a significant increase in detections during the passing of the energetic tidal jet. Encounter durations recorded by drifting C-PODs were longer than those recorded by moored C-PODs, suggesting that porpoises tended to move downstream with the flow rather than remaining stationary relative to the seabed or moving upstream. The energetic, turbulent conditions of the Great Race are clearly attractive to porpoises, and they track its movement with time; however, their structured movements in response to the evolving tidal situation cannot simply be represented as a direct relationship between current speed and porpoise presence.