Speaker
Description
Whale signals are frequently observed at triplets of hydrophones of the IMS hydroacoustic stations. Fin whale signals emit characteristic time-frequency patterns. Two types of fin whale signals are observed at IMS stations HA11, located close to Wake Island in the Pacific Ocean. Echoing of the signals is clear on the recorded traces and attributed to multiple bottom and sea surface reflections. Differential move-out between the direct arrivals, sea bottom and surface multiple reflections are modelled and interpreted as indication of the depths reached by the animals within a single dive. The waveforms resulting from the complex interaction between the direct signal and surface and sea bottom reflections signal are modelled. These observations and techniques provide a harmless way to record abundant observations of the animals’ diving behaviour and should help biologists in interpreting the time statistics and variations of the diving behaviour.
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