Ranging of Baleen Whale Calls using a Long Horizontal Array

Seismic surveys are under increasing scrutiny because of concern that they may disturb or otherwise harm marine mammals and impede their communications. Most of the energy from seismic surveys is low frequency, so the concern about their impact is focused on Baleen whales that communicate in the same frequency range. In this research study, data is analyzed from a seismic reflection experiment conducted by the R/V Langseth. Many Baleen whale calls have been recorded by the horizontal hydrophone array. Figure below shows two examples of Fin whale (higher frequency summer call) and Humpback whale calls.

Figure 1: The spectrogram of a Fin whale call (a) and a Humpback whale call (b).

The first call was recorded during the firing of the mitigation gun (the broadband impulsive signal after the whale call) and the second call was recorded during a complete shut-down.

I have developed a novel localization technique which utilizes the seismic hydrophone streamer to detect calling Baleen whales at greater range than possible with existing acoustic monitoring, and locate the calls to study whale behaviour. The calculated locations confirm the estimated locations reported by observers during the experiment.

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