Very-High-Frequency Acoustic Emissions from the White-Beaked Dolphin (Lagenorhynchus Albirostris)
Reception by sonar of the signals on board the Ministry of Agriculture, Fisheries and Food’s (MAFF’s) research vessel, CLIONE, from a school of white-beaked dolphins (Lagenorhynchus albirostris), shows that there is significant energy in their acoustic emissions to at least 325 kHz. A sector scanning sonar of 0.33° bearing resolution and 100 μs time resolution was used in active and passive modes when the dolphins approached the ship. Examples of the recorded pulse signals are shown in photographic sequences. Some of the analysed pulse rates varied from 100 to 750 pulses per second when averaged over 20ms periods. Crude estimates of the source level of the signals are between 123 to greater than 207 dB re 1 μPa at 1 m.
KeywordsAcoustic Emission Source Level Tidal Stream Spherical Spreading Signal Train
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- Arnold, G. P. Greer Walker, M. and Holford, B. H., 1990, Fish behaviour: achievements and potential of high-resolution sector-scanning sonar. Rapp. P.-v Réun. Cons. int Explor. Mer, XXX: in pressGoogle Scholar