| Summary: | The ability to monitor and differentiate vocalizations from a given marine mammal species can be challenging with single sensor measurements when there are multiple marine mammal species vocalizing in close proximity and when the vocalizations have not been observed or documented previously. Here we employ a large-aperature coherent hydrophone array system with directional sensing to detect, localize, and classify a repertoire of fin whale vocalizations using the passive ocean acoustic waveguide remote sensing (POAWRS) technique. The fin whale vocalizations are comprised of their characteristic 20 Hz centered pulses, interspersed by 130 Hz centered upsweep calls, and other vocalizations with frequencies ranging between 40-80 Hz. The directional sensing ability of POAWRS is essential for associating various call types to fin whales after long term tracking of the vocalization bearing-time trajectories and localizations over multiple diel cycles. Here we quantify the relative diel occurrence of the three distinct fin vocalization types and apply the results to infer their behaviors as a function of the observation region.
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