Southall Brandon L, Durban John W, Calambokidis John, Casey Caroline, Fahlbusch James A, Fearnbach Holly, Flynn Kiirsten R, Fregosi Selene, Friedlaender Ari S, Leander Samantha G M, Visser Fleur
Southall Environmental Associates, 9099 Soquel Drive, Suite 8, Aptos, CA 95003, USA.
Long Marine Laboratory, Institute of Marine Sciences, University of Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA.
R Soc Open Sci. 2024 Oct 23;11(10):240650. doi: 10.1098/rsos.240650. eCollection 2024 Oct.
Despite strong interest in how noise affects marine mammals, little is known for the most abundant and commonly exposed taxa. Social delphinids occur in groups of hundreds of individuals that travel quickly, change behaviour ephemerally and are not amenable to conventional tagging methods, posing challenges in quantifying noise impacts. We integrated drone-based photogrammetry, strategically placed acoustic recorders and broad-scale visual observations to provide complementary measurements of different aspects of behaviour for short- and long-beaked common dolphins. We measured behavioural responses during controlled exposure experiments (CEEs) of military mid-frequency (3-4 kHz) active sonar (MFAS) using simulated and actual Navy sonar sources. We used latent-state Bayesian models to evaluate response probability and persistence in exposure and post-exposure phases. Changes in subgroup movement and aggregation parameters were commonly detected during different phases of MFAS CEEs but not control CEEs. Responses were more evident in short-beaked common dolphins (= 14 CEEs), and a direct relationship between response probability and received level was observed. Long-beaked common dolphins ( = 20) showed less consistent responses, although contextual differences may have limited which movement responses could be detected. These are the first experimental behavioural response data for these abundant dolphins to directly inform impact assessments for military sonars.
尽管人们对噪声如何影响海洋哺乳动物有着浓厚兴趣，但对于数量最多且最常接触噪声的分类群却知之甚少。群居的海豚科动物成群出现，数量可达数百只，它们行动迅速，行为瞬息万变，且不适合采用传统的标记方法，这给量化噪声影响带来了挑战。我们整合了基于无人机的摄影测量技术、精心布置的声学记录器以及大规模的视觉观测，以对短吻和长吻普通海豚行为的不同方面进行补充测量。我们在使用模拟和实际海军声纳源进行的军事中频（3 - 4千赫）主动声纳（MFAS）控制暴露实验（CEEs）中测量行为反应。我们使用隐状态贝叶斯模型来评估暴露阶段和暴露后阶段的反应概率及持续性。在MFAS CEEs的不同阶段通常能检测到亚群运动和聚集参数的变化，但在对照CEEs中则未检测到。短吻普通海豚（= 14次CEEs）的反应更为明显，并且观察到反应概率与接收水平之间存在直接关系。长吻普通海豚（= 20次）的反应则不太一致，尽管环境差异可能限制了能够检测到的运动反应。这些是这些常见海豚的首批实验行为反应数据，可直接为军事声纳的影响评估提供依据。
