Time and tide: Seasonal, diel and tidal rhythms in Wadden Sea Harbour porpoises (Phocoena phocoena).

Autor: Zein B; 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., Woelfing B; Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany., Dähne M; German Oceanographic Museum, Stralsund, Mecklenburg-Vorpommern, Germany., Schaffeld T; Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany., Ludwig S; German Navy Headquarters, Geo-Information Division, METOC Support, Rostock, Germany., Rye JH; The Danish Coastal Authority, Ministry of Environment and Food of Denmark, Lemvig, Denmark., Baltzer J; Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany., Ruser A; Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany., Siebert U; Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum, Germany.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2019 Mar 20; Vol. 14 (3), pp. e0213348. Date of Electronic Publication: 2019 Mar 20 (Print Publication: 2019).
DOI: 10.1371/journal.pone.0213348
Abstrakt: 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.
Competing Interests: The authors have declared that no competing interest exist.
Databáze: MEDLINE
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