Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.
School of Geography & Geosciences, University of St Andrews, St Andrews, Fife, Scotland, United Kingdom.
PLoS One. 2019 Mar 20;14(3):e0213348. doi: 10.1371/journal.pone.0213348. eCollection 2019.
Odontocetes have evolved a rich diversity of prey- and habitat-specific foraging strategies, which allows them to feed opportunistically on locally and temporally abundant prey. While habitat-specific foraging strategies have been documented for some odontocete species, this is less known for the harbour porpoise (Phocoena phocoena). We collected multiple years of acoustic data using echolocation click loggers to analyse porpoise occurrence and buzzing behaviour, indicating feeding, in the German Wadden Sea (North Sea). Seasonal, diel and tidal effects were studied using Generalised Estimating Equations (GEE-GAMs). Locally season, time of day and tidal time significantly influenced the probability of porpoise detections and detection of foraging sequences (buzzes). Hunting strategies, and therefore frequency of buzzes, were likely affected by prey distribution and large differences between POD locations indicated that porpoises used highly specific behaviour adapted to tide and time of day to efficiently feed on the available prey. Strong seasonal and spatial variation in diel and tidal effects underline the importance of long-term observations. Studies on porpoise behaviour are often based on short-term observations and might rather reflect a seasonal than a general pattern. The results of this study show clearly that significant changes in porpoise behaviour can be found in short and long-term observations. Here some features are based on short term determinants and others are stable over years and care should be taken about drawing general conclusions based on local patterns. Highly variable spatio-temporal patterns indicate a high flexibility of porpoises in a highly variable environment and address a challenge for complex conservation management plans.
齿鲸类动物进化出了丰富多样的、针对特定猎物和栖息地的觅食策略，这使它们能够在当地和暂时丰富的猎物中机会性地觅食。虽然已经记录了一些齿鲸物种的特定栖息地觅食策略，但对于港湾海豚（Phocoena phocoena）来说，这方面的了解较少。我们使用回声定位点击记录器收集了多年的声学数据，以分析德国瓦登海（北海）中海豚的出现和嗡嗡声行为，这些行为表明海豚正在觅食。使用广义估计方程（GEE-GAMs）研究了季节性、昼夜和潮汐效应。局部季节、一天中的时间和潮汐时间显著影响了海豚检测和觅食序列（嗡嗡声）检测的概率。狩猎策略，因此嗡嗡声的频率，可能受到猎物分布的影响，而位置之间的 POD 差异很大，表明海豚使用高度特定的行为来适应潮汐和时间，以有效地捕食可用的猎物。昼夜和潮汐效应的季节性和空间变化强烈强调了长期观察的重要性。关于海豚行为的研究通常基于短期观察，并且可能反映的是季节性模式，而不是一般性模式。这项研究的结果清楚地表明，在短期和长期观察中都可以发现海豚行为的重大变化。这里的一些特征基于短期决定因素，而其他特征则多年保持稳定，因此在基于局部模式得出一般性结论时应谨慎行事。高度可变的时空模式表明，海豚在高度可变的环境中具有很高的灵活性，这对复杂的保护管理计划提出了挑战。
