Data from: Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises
Creators
- 1. University of Aberdeen
- 2. Kongsberg Maritime Ltd, 11 The Briars, Waterberry Drive, Waterlooville, Hampshire PO7 7YH, UK*
- 3. WWT Consulting, Slimbridge, Gloucestershire GL2 7BT, UK*
- 4. University of Bath
Description
Assessments of the impact of offshore energy developments are constrained because it is not known whether fine-scale behavioral 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 2-D seismic survey in the North Sea. Acoustic and visual data provided evidence of group responses to air-gun 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 of 145-151 dB re. 1µPa2 s. 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 to 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 sub-optimal 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.
Notes
Files
README_for_responses to seismic surveys.txt
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Additional details
Related works
- Is cited by
- 10.1098/rspb.2013.2001 (DOI)