Van Cise Amy M, Roch Marie A, Baird Robin W, Aran Mooney T, Barlow Jay
Scripps Institution of Oceanography, University of California-San Diego, La Jolla, California 92038, USA.
San Diego State University, San Diego, California 92182, USA.
J Acoust Soc Am. 2017 Feb;141(2):737. doi: 10.1121/1.4974858.
Divergence in acoustic signals used by different populations of marine mammals can be caused by a variety of environmental, hereditary, or social factors, and can indicate isolation between those populations. Two types of genetically and morphologically distinct short-finned pilot whales, called the Naisa- and Shiho-types when first described off Japan, have been identified in the Pacific Ocean. Acoustic differentiation between these types would support their designation as sub-species or species, and improve the understanding of their distribution in areas where genetic samples are difficult to obtain. Calls from two regions representing the two types were analyzed using 24 recordings from Hawai'i (Naisa-type) and 12 recordings from the eastern Pacific Ocean (Shiho-type). Calls from the two types were significantly differentiated in median start frequency, frequency range, and duration, and were significantly differentiated in the cumulative distribution of start frequency, frequency range, and duration. Gaussian mixture models were used to classify calls from the two different regions with 74% accuracy, which was significantly greater than chance. The results of these analyses indicate that the two types are acoustically distinct, which supports the hypothesis that the two types may be separate sub-species.
不同种群的海洋哺乳动物所使用的声学信号的差异可能由多种环境、遗传或社会因素引起，并且可能表明这些种群之间存在隔离。在太平洋中，已经识别出两种在基因和形态上不同的短鳍领航鲸，在首次于日本海域被描述时分别称为奈萨型和志保型。这两种类型之间的声学差异将支持将它们认定为亚种或物种，并有助于加深对它们在难以获取基因样本的地区的分布情况的了解。使用来自夏威夷的24份录音（奈萨型）和来自东太平洋的12份录音（志保型），对代表这两种类型的两个区域的叫声进行了分析。两种类型的叫声在起始频率中位数、频率范围和持续时间方面存在显著差异，并且在起始频率、频率范围和持续时间的累积分布上也存在显著差异。使用高斯混合模型对来自两个不同区域的叫声进行分类，准确率达到74%，这显著高于随机概率。这些分析结果表明，这两种类型在声学上是不同的，这支持了这两种类型可能是独立亚种的假设。
