Variation in harbour porpoise activity in response to seismic survey noise

Animals exposed to anthropogenic disturbance make trade-offs between perceived risk and the cost of leaving disturbed areas. Impact assessments tend to focus on overt behavioural responses leading to displacement, but trade-offs may also impact individual energy budgets through reduced foraging performance. Previous studies found no evidence for broad-scale displacement of harbour porpoises exposed to impulse noise from a 10 day two-dimensional seismic survey. Here, we used an array of passive acoustic loggers coupled with calibrated noise measurements to test whether the seismic survey influenced the activity patterns of porpoises remaining in the area. We showed that the probability of recording a buzz declined by 15% in the ensonified area and was positively related to distance from the source vessel. We also estimated received levels at the hydrophones and characterized the noise response curve. Our results demonstrate how environmental impact assessments can be developed to assess ...暴露于人为干扰的动物，会在感知到的风险与离开受干扰区域的代价之间做出权衡取舍。环境影响评估往往侧重于会引发栖息地移位的显性行为响应，但此类权衡对策亦可通过降低觅食效率，对个体的能量收支平衡造成影响。过往研究未发现，暴露于为期10天的二维地震勘探所产生的脉冲噪声中的港湾鼠海豚（harbour porpoise）存在大范围栖息地移位的证据。本研究采用被动声学记录仪（passive acoustic logger）阵列结合校准后的噪声测量方案，旨在探究此次地震勘探是否会对滞留在研究区域内的鼠海豚的活动模式产生影响。本研究发现，在噪声照射区域内，记录到觅食嗡鸣信号的概率下降了15%，且该概率与震源船的距离呈正相关；本研究还估算了水听器（hydrophone）处的噪声接收级，并对噪声响应曲线进行了特征刻画。本研究结果展示了环境影响评估可如何优化完善，以评估……