Dear colleagues and MARMAM Members,
On behalf of my co-authors I am pleased to share our recent publication in PLOS ONE:
Time and tide: Seasonal, diel and tidal rhythms in Wadden
Sea Harbour porpoises (Phocoena phocoena)
Zein B, Woelfing B, Dähne M, Schaffeld T, Ludwig S, et al. (2019) Time and tide: Seasonal, diel and tidal rhythms in Wadden Sea Harbour porpoises (Phocoena phocoena). PLOS ONE 14(3): e0213348
Abstract:
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.
The open-access paper can be downloaded here:
https://doi.org/10.1371/journal.pone.0213348.
Kind regards,
Tobias Schaffeld
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Tobias Schaffeld
Institute for Terrestrial and Aquatic Wildlife Research (ITAW)
University of Veterinary Medicine Hannover, Foundation
Werftstr. 6 / 25761 Büsum / Germany
Tel +49 511 856 8164 / Fax +49 511 856-8181
http://www.tiho-hannover.de/kliniken-institute/institute/institut-fuer-terrestrische-und-aquatische-wildtierforschung/
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