Cooperative Institute for Marine Resources Studies, Hatfield Marine Science Center, Oregon State University, 2030 Marine Science Drive, Newport, Oregon 97365, USA.
J Acoust Soc Am. 2010 Jul;128(1):474-9. doi: 10.1121/1.3442362.
This study provides a comprehensive description of the acoustic characteristics of the predominant long-range underwater vocalizations of the crabeater seal, Lobodon carcinophaga, derived from stationary and continuous long-term recordings obtained in the Southern Ocean in 2007. Visual screening of data recorded between 1 October and 15 December 2007 indicates that the principal period of vocal activity of the crabeater seal is the latter part of October and all of November, coinciding with the breeding season of this species. Two call types were identified during this period: the low moan call, which has been described in previous studies and the high moan call, a call type newly described here. Out of 17 052 manually extracted crabeater seal calls, high-quality recordings of 152 low moans and 86 high moans with a signal-to-noise ratio exceeding 15 dB were selected and call-specific acoustic features were determined. While the mean duration of the two call types was comparable ( approximately 2.5 s), the high moan occurred at notably higher frequencies (1000-4900 Hz) than the low moan (260-2500 Hz). This study provides baseline information necessary to develop automated detection algorithms to facilitate systematic screening of extended data sets for crabeater seal vocalizations.
本研究全面描述了食蟹海豹（Lobodon carcinophaga）主要的远程水下发声特征，这些特征来自 2007 年在南大洋进行的固定和连续长期记录。对 2007 年 10 月 1 日至 12 月 15 日期间记录的数据进行视觉筛选表明，食蟹海豹的主要发声期是 10 月下旬和 11 月的全部时间，这与该物种的繁殖季节相吻合。在此期间确定了两种叫声类型：低频呻吟声，先前的研究中已有描述；高频呻吟声，这是一种新描述的叫声类型。在 17052 次手动提取的食蟹海豹叫声中，选择了信噪比超过 15dB 的 152 次低频呻吟声和 86 次高频呻吟声的高质量记录，并确定了特定叫声的声学特征。虽然这两种叫声的平均持续时间相当（约 2.5 秒），但高频呻吟声的频率明显高于低频呻吟声（260-2500Hz）（1000-4900Hz）。本研究提供了必要的基线信息，以开发自动检测算法，从而方便对食蟹海豹发声的扩展数据集进行系统筛选。
