Acoustically invisible feeding blue whales in Northern Icelandic waters

作者：Akamatsu Tomonari^*; Rasmussen Marianne Helene; Iversen Maria

来源：Journal of the Acoustical Society of America, 2014, 136(2): 939-944.

DOI：10.1121/1.4887439

Fixed passive acoustic monitoring can be used for long-term recording of vocalizing cetaceans. Both presence monitoring and animal density estimation requires the call rates and sound source levels of vocalizations produced by single animals. In this study, blue whale calls were recorded using acoustic bio-logging systems in Skjalfandi Bay off Husavik, Northeast Iceland, in June 2012. An accelerometer was attached to individual whales to monitor diving behavior. During 21 h recording two individuals, 8 h 45 min and 13 h 2 min, respectively, 105 and 104 lunge feeding events and four calls were recorded. All recorded calls were down-sweep calls ranging from 105 to 48Hz. The sound duration was 1-2 s. The source level was estimated to be between 158 and 169 dB re 1 mu Pa rms, assuming spherical sound propagation from the possible sound source location to the tag. The observed sound production rates and source levels of individual blue whales during feeding were extremely small compared with those observed previously in breeding grounds. The feeding whales were nearly acoustically invisible. The function of calls during feeding remains unknown.

• 出版日期2014-8