Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises

Paul M. Thompson, Kate L. Brookes, Isla M. Graham, Tim R. Barton, Keith Needham, Gareth Bradbury, Nathan D. Merchant

Research output: Contribution to journalArticle

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Abstract

Assessments of the impact of offshore energy developments are constrained because it is not known whether fine-scale behavioural responses to noise lead to broader-scale displacement of protected small cetaceans. We used passive acoustic monitoring and digital aerial surveys to study changes in the occurrence of harbour porpoises across a 2000 km2 study area during a commercial two-dimensional seismic survey in the North Sea. Acoustic and visual data provided evidence of group responses to airgun noise from the 470 cu inch array over ranges of 5–10 km, at received peak-to-peak sound pressure levels of 165–172 dB re 1 µPa and sound exposure levels (SELs) of 145–151 dB re 1 µPa2 s−1. However, animals were typically detected again at affected sites within a few hours, and the level of response declined through the 10 day survey. Overall, acoustic detections decreased significantly during the survey period in the impact area compared with a control area, but this effect was small in relation to natural variation. These results demonstrate that prolonged seismic survey noise did not lead to broader-scale displacement into suboptimal or higher-risk habitats, and suggest that impact assessments should focus on sub-lethal effects resulting from changes in foraging performance of animals within affected sites.
Original languageEnglish
Article number20132001
Number of pages8
JournalProceedings of the Royal Society of London. B, Biological Sciences
Volume280
Issue number1771
Early online date2 Oct 2013
DOIs
Publication statusPublished - 22 Nov 2013

Fingerprint

Phocoena
Phocoena phocoena
porpoise
seismic survey
Ports and harbors
harbor
acoustics
disturbance
Acoustics
Noise
aerial survey
sublethal effect
animal
cetacean
behavioral response
Animals
Acoustic waves
sublethal effects
animal performance
habitat

Keywords

  • Marine Spatial Planning
  • Oil and gas exploration
  • Acoustic Disturbance
  • Marine Mammal Conservation
  • Phocoena phocoena

Cite this

Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises. / Thompson, Paul M.; Brookes, Kate L.; Graham, Isla M.; Barton, Tim R. ; Needham, Keith; Bradbury, Gareth; Merchant, Nathan D. .

In: Proceedings of the Royal Society of London. B, Biological Sciences, Vol. 280, No. 1771, 20132001, 22.11.2013.

Research output: Contribution to journalArticle

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