McNamara Riona M, Dunlop Rebecca A
School of the Environment, The University of Queensland, St Lucia, QLD, 4072, Australia.
School of the Environment, The University of Queensland, St Lucia, QLD, 4072, Australia.
Mar Environ Res. 2025 Oct;211:107415. doi: 10.1016/j.marenvres.2025.107415. Epub 2025 Jul 30.
Seismic air gun operations, used for oil and gas exploration, create intense, impulsive signals that can last for days or months. In response to these signals, baleen whales have been shown to change their feeding, breeding, and migratory behaviours, but with highly variable vocal responses. Some studies show an increase in calling activity and call level, suggesting a response indicative of a Lombard response to noise, whereas others found whales decreased call rate and level, suggesting an avoidance response. This study aimed to determine if humpback whales (Megaptera novaeangliae) significantly altered the rate and/or source level of their social calls in response to seismic air gun signals and determined if any changes were outside of 'normal' baseline vocal behaviour. Air guns ranged in size from a small 20 cubic inch gun to a 3130 cubic inch large commercial array, firing every 11 s and towed along a set transect. Individual humpback whales that were exposed to operational air guns were tagged using suction-cup acoustic tags (n = 12). Within these individuals, call rates and call source levels were compared during exposure to air guns, to before exposure. Then, the call rate and source level of whales exposed to air guns were compared to tagged whales that had not been exposed to air guns (n = 21). Results show that whales exposed to air guns generally increased their call rate and call source level, and these call rates and levels were significantly greater compared to unexposed tagged whales. This is consistent with a Lombard response to noise. However, not all tagged whales responded, nor was there a dose-response relationship between air gun received level, air gun proximity, and vocal response. Humpback whales' vocal responses to air guns are inconsistent and may be context-dependent, emphasising the need to understand how whales perceive these signals to assess the true ecological impact of air gun noise.
用于石油和天然气勘探的地震气枪作业会产生强烈的脉冲信号，这些信号可能持续数天或数月。研究表明，须鲸会对这些信号做出反应，改变它们的觅食、繁殖和迁徙行为，但发声反应却高度多变。一些研究显示鸣叫活动和鸣叫水平增加，表明这是对噪声的伦巴德反应；而另一些研究则发现鲸鱼的鸣叫速率和水平降低，表明是一种回避反应。本研究旨在确定座头鲸（Megaptera novaeangliae）是否会因地震气枪信号而显著改变其社交鸣叫的速率和/或声源水平，并确定任何变化是否超出“正常”的基线发声行为范围。气枪大小从小型的20立方英寸气枪到3130立方英寸的大型商业阵列不等，每隔11秒发射一次，并沿设定的断面拖曳。使用吸盘式声学标签标记了暴露于作业气枪的个体座头鲸（n = 12）。在这些个体中，将暴露于气枪期间的鸣叫速率和声源水平与暴露前进行比较。然后，将暴露于气枪的鲸鱼的鸣叫速率和声源水平与未暴露于气枪的标记鲸鱼（n = 21）进行比较。结果表明，暴露于气枪的鲸鱼通常会提高其鸣叫速率和声源水平，与未暴露的标记鲸鱼相比，这些鸣叫速率和水平显著更高。这与对噪声的伦巴德反应一致。然而，并非所有标记的鲸鱼都有反应，气枪接收水平、气枪距离和发声反应之间也不存在剂量反应关系。座头鲸对气枪的发声反应不一致，可能取决于具体情境，这凸显了了解鲸鱼如何感知这些信号以评估气枪噪声的真正生态影响的必要性。
