Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, USA.
Bioacoustics Research Program, Cornell Laboratory of Ornithology, Cornell University, Ithaca, NY, USA.
Biol Lett. 2018 Oct 24;14(10):20180484. doi: 10.1098/rsbl.2018.0484.
Ocean noise varies spatially and temporally and is driven by natural and anthropogenic processes. Increased ambient noise levels can cause signal masking and communication impairment, affecting fitness and recruitment success. However, the effects of increasing ambient noise levels on marine species, such as marine mammals that primarily rely on sound for communication, are not well understood. We investigated the effects of concurrent ambient noise levels on social whistle calls produced by bottlenose dolphins () in the western North Atlantic. Elevated ambient noise levels were mainly caused by ship noise. Increases in ship noise, both within and below the dolphins' call bandwidth, resulted in higher dolphin whistle frequencies and a reduction in whistle contour complexity, an acoustic feature associated with individual identification. Consequently, the noise-induced simplification of dolphin whistles may reduce the information content in these acoustic signals and decrease effective communication, parent-offspring proximity or group cohesion.
海洋噪声具有空间和时间上的变化，并受到自然和人为过程的驱动。环境噪声水平的增加会导致信号掩蔽和通讯障碍，从而影响生物的适应性和繁殖成功率。然而，增加的环境噪声水平对海洋物种的影响，例如主要依赖声音进行通讯的海洋哺乳动物，还不是很清楚。我们研究了同时存在的环境噪声水平对北大西洋西部宽吻海豚发出的社交哨声的影响。升高的环境噪声水平主要是由船只噪声引起的。船只噪声的增加，无论是在海豚叫声带宽内还是带宽外，都会导致海豚哨声频率升高，哨声轮廓复杂性降低，而这种复杂性与个体识别有关。因此，海豚哨声的这种由噪声引起的简化可能会降低这些声信号中的信息含量，并降低有效通讯、亲代与后代的接近程度或群体凝聚力。
