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

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