Beaked whale ( Ziphiidae ) foraging along Australia's Northwest Shelf

Abstract

Beaked whales are elusive deep-diving odontocetes, and their distribution and foraging ecology remain poorly documented in Australian waters. This study presents a passive acoustic monitoring (PAM)-based assessment of beaked whale foraging activity along Australia's Northwest Shelf—a continental shelf region with features typically conducive to beaked whale sustenance. The area is also of economic significance due to ongoing offshore oil and gas production, commercial fishing, and commercial shipping, raising concerns about potential impacts on these deep-diving cetaceans. This study collected year-long underwater acoustic datasets from three deep-water sites in the region. Using a semi-automated workflow based on correlogram visualizations, the study identified beaked whale foraging buzzes—short, rapid echolocation click trains associated with prey capture attempts. Analyses revealed year-round foraging activity, with significantly higher levels at night, but no strong spatial or seasonal variations across the study area. These findings suggest persistent use of the region by beaked whales despite offshore industry presence, underscoring the ecological significance of these deep-water habitats. This study highlights the value of PAM, combined with efficient analytical approaches, for monitoring cryptic species in data-limited, industrialized marine environments.