Abstract：
Multiple whale-watching vessels may operate around cetaceans at any one time, and targeted animals may experience underwater noise effects. We hypothesised that the cumulative noise of two vessels with low source levels (SLs) will elicit lower behavioural disturbance in short-finned pilot whales (Globicephala macrorhynchus) compared to a single vessel with a higher SL. We measured the behaviour of whales during 26 controls (stationary vessel >300 m) and 44 treatments off Tenerife (Canary Islands, Spain). Treatments consisted of vessel approaches mimicking whale-watch scenarios (distance ∼60 m, speed 1.5 kn). Approaches with two simultaneous vessels, with maximum cumulative mid and low-frequency (0.2-110 kHz) weighted source levels (SLsMF-LF) 137-143 dB, did not affect mother-calf pairs\' resting, nursing, diving, respiration rate or inter-breath interval. However, a louder single vessel approach with twin petrol engines at SLsMF-LF 139-151 dB significantly decreased the proportion of time resting for the mother. The results suggest that if a single or two vessels are present, if the cumulative SL is < 143 dB, the behavioural disturbance on the whales will be negligible. By examining noise effects from multiple vessels on the behaviour of pilot whales, the importance of incorporating a noise threshold into whale-watching guidelines was emphasised.
摘要：
多个观鲸船只可能在任何时候围绕鲸类活动，目标动物可能会受到水下噪音的影响。我们假设，与具有较高SL的单艘船相比，具有低源水平（SL）的两艘船的累积噪声将在短鳍领航鲸（Globicephalamacrorhynchus）中引起较低的行为干扰。我们在特内里费岛（加那利群岛，西班牙)。治疗包括模仿观鲸场景的船只进近(距离约60米，速度1.5kn)。接近两个同时的船只，最大累积中低频（0.2-110kHz）加权源电平（SLsMF-LF）137-143dB，不影响母牛对的休息，护理,潜水,呼吸频率或呼吸间隔。然而,在SLsMF-LF139-151dB处使用双汽油发动机的更大声的单船方法显着降低了母亲休息时间的比例。结果表明，如果存在单个或两个血管，如果累积SL<143dB，鲸鱼的行为障碍可以忽略不计。通过检查来自多个船只的噪音对领航鲸行为的影响，强调了将噪声阈值纳入观鲸指南的重要性。
