Marine Science Department, University of Otago, P.O. Box 56, Dunedin, 9001 New Zealand.
J Acoust Soc Am. 2011 Jul;130(1):568-73. doi: 10.1121/1.3578455.
Sperm whales (Physeter macrocephalus) emit short, broadband clicks which often include multiple pulses. The time interval between these pulses [inter-pulse interval (IPI)] represents the two-way time for a pulse to travel between the air sacs located at either end of the sperm whale's head. The IPI therefore, is a proxy of head length which, using an allometric relationship, can be used to estimate total body length. Previous studies relating IPI to an independent measure of length have relied on very small sample sizes and manual techniques for measuring IPI. Sound recordings and digital stereo photogrammetric measurements of 21 individuals were made off Kaikoura, New Zealand, and, in addition, archived recordings of whales measured with a previous photogrammetric system were reanalyzed to obtain a total sample size of 33 individuals. IPIs were measured automatically via cepstral analysis implemented via a software plug-in for pamguard, an open-source software package for passive acoustic monitoring. IPI measurements were highly consistent within individuals (mean CV=0.63%). The new regression relationship relating IPI (I) and total length (T) was found to be T=1.258I+5.736 (r(2)=0.77, p<0.001). This new regression provides a better fit than previous studies of large (> 11 m) sperm whales.
抹香鲸（Physeter macrocephalus）会发出短促的宽带咔嗒声，其中通常包含多个脉冲。这些脉冲之间的时间间隔 [脉冲间隔 (IPI)] 代表脉冲在抹香鲸头部两端的气囊之间往返传播的时间。因此，IPI 是头部长度的代理，使用一种幂函数关系，可以用来估计总体长。以前将 IPI 与独立的长度测量值相关联的研究依赖于非常小的样本量和手动测量 IPI 的技术。在新西兰凯库拉（Kaikoura）进行了 21 头个体的录音和数字立体声摄影测量，并重新分析了以前使用摄影测量系统测量的鲸鱼的存档录音，以获得总共 33 头个体的样本量。通过 cepstral 分析自动测量 IPI，该分析通过 pamguard 的软件插件实现，pamguard 是一个用于被动声学监测的开源软件包。个体内的 IPI 测量值高度一致（平均 CV=0.63%）。发现新的 IPI（I）和总长度（T）之间的回归关系为 T=1.258I+5.736（r(2)=0.77，p<0.001）。与以前对大型 (> 11 m) 抹香鲸的研究相比，这个新的回归提供了更好的拟合。
