Data_Sheet_1_Assessing the Role of Sampling Uncertainty When Predicting Behavioral Responses of Tagged Cetaceans Exposed to Naval Sonar.pdf

Concerns over cetacean mortality events coincident with maritime warfare exercises have motivated efforts to characterize the effects of anthropogenic noise on free-ranging whales and dolphins. By monitoring the movement, diving, and acoustic behaviors of individual whales before, during, and after sound exposure, behavioral response studies (BRSs) have supported significant progress in our understanding of the sensitivity of various cetacean species to high-powered naval sonar signals. However, differences in the designs and sampling capabilities of animal-borne tags typically used in BRS experiments prompt questions about the influence of data resolution in quantitative assessments of noise impacts. We conducted simulations to examine how uncertainty in the acoustic dose either measured on high-resolution multi-sensor biologging tags or modeled from position-transmitting satellite telemetry tags may affect predictions of behavioral responses in Cuvier’s beaked whales (Ziphius cavirostris) exposed to low- and mid-frequency active sonar. We considered an array of scenarios representative of real-world BRSs and used posterior estimates of dose-response functions obtained under an established Bayesian hierarchical modeling framework to explore the consequences of different tag choices for management decision-making. Our results indicate that (1) the zone of impact from a sonar source is under-estimated in most test conditions, (2) substantial reductions in the uncertainty surrounding dose-response relationships are possible at higher sample sizes, and (3) this largely holds true irrespective of tag choice under the scenarios considered, unless positional fixes from satellite tags are consistently poor. Strategic monitoring approaches that combine both archival biologging and satellite biotelemetry are essential for characterizing complex patterns of behavioral change in cetaceans exposed to increasing levels of acoustic disturbance. We suggest ways in which BRS protocols can be optimized to curtail the effects of uncertainty.

关于与海上军事演习同时发生的鲸类死亡事件的担忧，促使人们努力描绘人类噪声对自由游弋的鲸鱼和海豚的影响。通过监测个体鲸鱼在声暴露前、中、后的移动、潜水及声学行为，行为响应研究（BRS）支持了我们对各种鲸类物种对高功率海军声纳信号的敏感性理解取得了显著进展。然而，动物携带标签在BRS实验中设计及采样能力的差异，引发了关于数据分辨率在噪声影响定量评估中影响的疑问。我们进行了模拟实验，以检验声剂量不确定性的影响，该不确定性要么是通过高分辨率多传感器生物定位标签测量得到，要么是从位置传输的卫星遥测标签模拟得到，可能如何影响受到低频和中频主动声纳暴露的库维氏喙鲸（Ziphius cavirostris）的行为响应预测。我们考虑了一系列代表真实世界BRS的情景，并利用在建立的贝叶斯层次建模框架下获得的剂量-反应函数的后验估计，探讨了不同标签选择对管理决策的影响。我们的结果表明：（1）在大多数测试条件下，声源的影响区域被低估；（2）在较大的样本量下，可以显著减少剂量-反应关系的不确定性；（3）在考虑的情景下，这一结论在很大程度上与标签选择无关，除非卫星标签的位置固定始终较差。结合存档生物定位和卫星生物遥测的战略监测方法对于描绘鲸类在声学干扰水平不断上升的情况下复杂的行为变化模式至关重要。我们提出了优化BRS方案以缩减不确定性的影响的方法。