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

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....

近海能源开发的影响评估常受限于认知空白——目前尚不明确，针对噪声的精细尺度行为响应是否会引发受保护小型鲸类的更大尺度位移。本研究采用被动声学监测（passive acoustic monitoring）与数字航空调查手段，针对北海某商业二维地震勘探（2-D seismic survey）期间，2000平方千米研究海域内港湾鼠海豚的出现频次变化开展研究。声学与视觉观测数据显示，在接收峰峰值声压级为165~172 dB re 1 µPa、声暴露级为145~151 dB re 1 µPa²·s的条件下，该470立方英寸气枪阵列所产生的噪声，会在5~10千米范围内引发群体行为响应。但受影响海域通常可在数小时内再次观测到该类动物，且响应强度在为期10天的勘探过程中逐渐减弱。整体而言，相较于对照区域，勘探期间影响区域内的声学观测检出率显著下降，但该效应相较于自然波动而言幅度较小。