Hector's dolphin movement patterns in response to height and direction of ocean swell

A central question to any understanding of ecology is how animals use their habitat, and how habitat use is influenced by temporally changing features of the environment. Previous research on Hector's dolphins at Akaroa Harbour, New Zealand suggested that dolphins leave inshore, harbour environments during or after rough weather. To test this hypothesis, visual sightings (2000–2012) and acoustic detections (2007–2008) of Hector's dolphins in Akaroa Harbour were modelled to test for a relationship with swell height and swell direction. Sighting rates and acoustic detection rates in Akaroa Harbour were significantly lower on days after big swell events and in some linear models after swell events from the south. These results indicate that swell events influence Hector's dolphin movements in and around Akaroa Harbour. Possible reasons for this behaviour are diverse and need further investigation. However, this information can be used both to predict daily dolphin movement for conservation and research purposes, and to suggest how dolphins may react in future if extreme weather events are becoming frequent.

生态学认知的核心议题之一，在于动物如何利用其栖息地，以及栖息地利用方式如何受环境随时间变化的特征所影响。此前针对新西兰阿卡罗阿港（Akaroa Harbour）赫氏矮海豚（Hector's Dolphin）的研究表明，这类海豚会在恶劣天气期间或之后离开近岸港域环境。为验证这一假说，研究团队对2000年至2012年的赫氏矮海豚目视目击数据，以及2007年至2008年的该种群在阿卡罗阿港的声学探测数据进行建模，以检验其与浪高、浪向的关联。阿卡罗阿港的目击率与声学探测率，在强涌浪事件后的次日显著偏低；部分线性模型结果还显示，来自南向的涌浪事件后，上述两类检出率同样存在显著下降。上述结果表明，涌浪事件会影响赫氏矮海豚在阿卡罗阿港及其周边水域的活动移动。该行为背后的潜在诱因多种多样，有待进一步研究探明。不过，本研究所得信息既可用于为保护与科研工作预测海豚的每日活动轨迹，也可用于推演在极端天气事件愈发频发的未来，海豚可能做出的行为响应。