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Vessel noise exposures of harbour seals from the Wadden Sea

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review


  • Dominik André Nachtsheim, University of Veterinary Medicine Hannover
  • ,
  • Mark Johnson
  • Tobias Schaffeld, University of Veterinary Medicine Hannover
  • ,
  • Abbo van Neer, University of Veterinary Medicine Hannover
  • ,
  • Peter T. Madsen
  • Charlotte R. Findlay
  • Laia Rojano-Doñate
  • Jonas Teilmann
  • Lonnie Mikkelsen, Norwegian Polar Institute
  • ,
  • Johannes Baltzer, University of Veterinary Medicine Hannover
  • ,
  • Andreas Ruser, University of Veterinary Medicine Hannover
  • ,
  • Ursula Siebert
  • Joseph G. Schnitzler, University of Veterinary Medicine Hannover

The North Sea faces intense ship traffic owing to increasing human activities at sea. As harbour seals (Phoca vitulina) are abundant top predators in the North Sea, it is hypothesised that they experience repeated, high-amplitude vessel exposures. Here, we test this hypothesis by quantifying vessel noise exposures from deployments of long-term sound and movement tags (DTAGs) on nine harbour seals from the Wadden Sea. An automated tool was developed to detect intervals of elevated noise in the sound recordings. An assessment by multiple raters was performed to classify the source as either vessels or other sounds. A total of 133 vessel passes were identified with received levels > 97 dB re 1µPa RMS in the 2 kHz decidecade band and with ambient noise > 6 dB below this detection threshold. Tagged seals spent most of their time within Marine Protected Areas (89 ± 13%, mean ± SD) and were exposed to high-amplitude vessel passes 4.3 ± 1.6 times per day. Only 32% of vessel passes were plausibly associated with an AIS-registered vessel. We conclude that seals in industrialized waters are exposed repeatedly to vessel noise, even in areas designated as protected, and that exposures are poorly predicted by AIS data.

TidsskriftScientific Reports
StatusUdgivet - apr. 2023

Bibliografisk note

Funding Information:
The study was funded by the German Federal Agency for Nature Conservation (BfN) under the projects “Effects of underwater noise on marine vertebrates” (Cluster 7, Z1.2-53302/2010/14) and “Under Water Noise Effects—UWE” (FKZ 3515822000), and as part of the SATURN project, which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101006443. The seal catches were funded and supported by the Schleswig-Holstein’s Government-Owned Company for Coastal Protection, National Parks and Ocean Protection (LKN). We would like to thank all helpers during the seal catches and tag recovery. We are especially grateful to Heather Vance for help in tag preparation and calibration. We are thankful to Mirko Hauswirth (BfN) and Emily Griffiths (Aarhus University) for providing AIS data from German and Danish waters, respectively. MJ was supported for development of the tags by a Marie Curie-Sklodowska Career Integration Grant (EU-FP7) and by MASTS, the Marine Alliance for Science and Technology Scotland. We are grateful to two anonymous reviewers for their constructive feedback which has improved our manuscript substantially.

Publisher Copyright:
© 2023, The Author(s).

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