Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand.
J Acoust Soc Am. 2013 Sep;134(3):2438-45. doi: 10.1121/1.4816564.
A non-invasive acoustic method for measuring the growth of sperm whales was developed based on estimating the length of individuals by measuring the inter-pulse interval (IPI) of their clicks. Most prior knowledge of growth in male sperm whales has come from from fitting growth curves to length data gained from whaling. Recordings made at Kaikoura, New Zealand, were used to estimate the length and growth of 32 photographically identified, resident whales that have been recorded repeatedly between 1991 and 2009. All whales recorded more than six months apart (n = 30) showed an increase in IPI. Using established relationships between IPI and total length, it was found that the average growth rate in the Kaikoura population is lower, especially for smaller whales (13-14.5 m), than that derived from historical whaling data from other populations. This difference may be due to ecological differences among populations but might also reflect upward bias in measurements gained in whaling. The ability to track growth of individuals through time is only possible via non-lethal means and offers a fundamentally different kind of data because differences among individuals can be measured.
一种非侵入性的声学方法被开发出来，用于测量抹香鲸的生长情况，该方法基于通过测量个体的脉冲间隔（IPI）来估计个体的长度。雄性抹香鲸生长的大部分先前知识来自于通过拟合生长曲线来获得从捕鲸中获得的长度数据。在新西兰凯库拉进行的记录被用于估计 32 头经拍照确认的、居住在那里的鲸鱼的长度和生长情况，这些鲸鱼在 1991 年至 2009 年期间被反复记录。所有记录时间相隔超过六个月的鲸鱼（n = 30）的 IPI 都有所增加。利用 IPI 与总长度之间的既定关系，发现凯库拉种群的平均生长速度较低，尤其是对于较小的鲸鱼（13-14.5 米），低于从其他种群的历史捕鲸数据中得出的速度。这种差异可能是由于种群之间的生态差异造成的，但也可能反映了捕鲸中获得的测量值存在向上的偏差。只有通过非致命手段才能跟踪个体随时间的生长情况，这提供了一种截然不同的数据，因为可以测量个体之间的差异。
