Tsutsumi Chika, Ichikawa Kotaro, Arai Nobuaki, Akamatsu Tomonari, Shinke Tomio, Hara Takeshi, Adulyanukosol Kanjana
Graduate School of Informatics, Kyoto University, 606-8501 Kyoto, Japan.
J Acoust Soc Am. 2006 Sep;120(3):1356-60. doi: 10.1121/1.2221529.
Little is known about feeding behavior of wild dugongs (Dugong dugon) because direct measurements of feeding events in the water were scarcely feasible. In this study, the authors achieved the first successful feeding sound monitoring in a seagrass area using a full-band underwater recording system (called automatic underwater sound monitoring system for dugong: AUSOMS-D). In total, 175 feeding sounds were identified in 205 h of recording. Feeding sounds were only detected at night, implying diurnal differences in the feeding behavior of the studied dugong population. Differences in periodicity of feeding sounds suggested that two or more individuals were in the acoustically observable area. Furthermore, a feeding position monitored by two AUSOMS-Ds was used to calculate source levels of dugong feeding sounds. Assuming spherical_propagation, source levels were measured between 70.6 and 79.0 dB rms re 1 microPa/square root of Hz.
由于几乎无法在水中直接测量儒艮的进食事件，因此对野生儒艮（Dugong dugon）的进食行为了解甚少。在本研究中，作者使用全频段水下记录系统（称为儒艮自动水下声音监测系统：AUSOMS-D）首次成功地在海草区域监测到了进食声音。在205小时的记录中，总共识别出175次进食声音。进食声音仅在夜间被检测到，这意味着所研究的儒艮种群的进食行为存在昼夜差异。进食声音的周期性差异表明，有两个或更多个体处于声学可观测区域。此外，利用两个AUSOMS-D监测到的一个进食位置来计算儒艮进食声音的声源级。假设为球面传播，测量得到的声源级在70.6至79.0 dB rms re 1微帕/赫兹平方根之间。
