Classification of Bering‐Chukchi‐Beaufort Bowhead Whale Calls

ABSTRACT

Bowhead whales ( Balaena mysticetus ) are an endemic species to the Arctic Ocean and are highly reliant upon acoustic communication. Despite being one of the most thoroughly studied populations of bowhead whales, we still have a poor understanding of the calling behavior of Bering‐Chukchi‐Beaufort (BCB) bowhead whales. In order to address this knowledge gap, we extracted 2326 bowhead whale calls from passive acoustic recordings taken between 2018 and 2021 at eight bottom‐mounted hydrophone recording sites across the eastern Beaufort Sea and Amundsen Gulf. Using a random forest model, we classified eight distinct call categories based on 16 acoustic features with 86% accuracy. We present descriptive statistics for these different call categories, highlighting the most important acoustic features used in differentiating between them. By quantitatively describing these calls and defining the vocal repertoire of BCB bowhead whales, this study lays important groundwork for examining the acoustic ecology of this highly vocal marine species. These results provide a basis to test hypotheses regarding the association of various calls and behaviors in order to assess call function, as well as building an acoustic morphology database for future call detectors and dialect comparison with other bowhead whale populations.