The harbour porpoise Phocoena phocoena is a small marine predator with a high conservation status in Europe and the USA. To protect the species effectively, it is crucial to understand its movement patterns and how the distribution of intensively used foraging areas can be predicted from environmental conditions. Here, we investigated the influence of both static and dynamic environmental conditions on large-scale harbour porpoise movements in the North Sea. We used long-term movement data from 57 individuals tracked during 1999−2017 in a state-space model to estimate the underlying behavioural states, i.e. whether animals used area-restricted or directed movements. Subsequently, we assessed whether the probability of using area-restricted movements was related to environmental conditions using a generalized linear mixed model. Harbour porpoises were more likely to use area-restricted movements in areas with low salinity levels, relatively high chlorophyll a concentrations and low current velocity, and in areas with steep bottom slopes, suggesting that such areas are important foraging grounds for porpoises. Our study identifies environmental parameters of relevance for predicting harbour porpoise foraging hot spots over space and time in a dynamic system. The study illustrates how movement patterns and data on environmental conditions can be combined, which is valuable to the conservation of marine mammals.

中文翻译：

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长期港湾鼠海豚运动数据的行为状态建模和环境变化的影响

港湾鼠海豚 Phocoena phocoena 是一种小型海洋捕食者，在欧洲和美国具有较高的保护地位。为了有效保护该物种，了解其运动模式以及如何根据环境条件预测密集使用的觅食区的分布至关重要。在这里，我们调查了静态和动态环境条件对北海大型港湾鼠海豚运动的影响。我们使用 1999-2017 年在状态空间模型中跟踪的 57 个人的长期运动数据来估计潜在的行为状态，即动物是否使用区域限制或定向运动。随后，我们使用广义线性混合模型评估了使用区域限制运动的概率是否与环境条件相关。港湾鼠海豚更有可能在盐度低、叶绿素 a 浓度相对较高且流速较低的地区以及底部坡度较陡的地区进行区域限制运动，这表明这些地区是鼠海豚的重要觅食地。我们的研究确定了与预测动态系统中空间和时间上的港湾鼠海豚觅食热点相关的环境参数。该研究说明了如何将运动模式和环境条件数据结合起来，这对海洋哺乳动物的保护很有价值。我们的研究确定了与预测动态系统中空间和时间上的港湾鼠海豚觅食热点相关的环境参数。该研究说明了如何将运动模式和环境条件数据结合起来，这对海洋哺乳动物的保护很有价值。我们的研究确定了与预测动态系统中空间和时间上的港湾鼠海豚觅食热点相关的环境参数。该研究说明了如何将运动模式和环境条件数据结合起来，这对海洋哺乳动物的保护很有价值。