Researchers have managed to successfully record the sounds of the elusive and mysterious beaked whale in the Foz do Amazonas Basin off northern Brazil.
These majestic creatures represent one of the least understood groups of marine mammals. This is primarily due to their elusive behavior, deep offshore habitat and limited surface sound production.
While whale-watch enthusiasts routinely observe popular cetaceans like blue whales and orcas, beaked whales spend minimal time at the surface and may dive to depths of 3,000 meters/9,842 feet for more than two hours at a time. These characteristics, combined with predatory pressure from sharks and killer whales, underscore the challenges of studying their ecology and biodiversity.
Researchers studied the whales in the Foz do Amazonas Basin between 2022 and 2024, successfully documenting the whales’ acoustic parameters. The team successfully captured nine acoustic recordings and had four visual encounters, documenting at least three distinct beaked whale species.
This research marks the first documentation of acoustic parameters for beaked whales in Brazilian waters. It also provides a proof of concept to passive acoustic monitoring as a reliable method for studying elusive marine fauna.
Commenting on the findings, author Raphael Barbosa Machado stated:
“The motivation for this research arose from the need to expand knowledge on cetacean biodiversity in Brazilian waters, with particular attention to deep-diving species such as beaked whales. This study provides the first documentation of acoustic parameters of beaked whales in Brazilian waters, while also contributing new information on cetacean biodiversity in northern Brazil.
As the number of detections increases — particularly simultaneous visual and acoustic records — our ability to reliably associate specific acoustic signals with visually confirmed species will also improve. Addressing these knowledge gaps is essential for informing public policies and guiding conservation and management efforts aimed at safeguarding these elusive species.”
Read the full report here.
