Listening to the Deep: Antarctic Whale Research Breaks New Ground in the Gerlache Strait

SoundTraps are compact, lightweight, autonomous underwater acoustic recorders designed to monitor marine life, such as whales, over extended periods. In the picture, Heidi Ahonen is thrilled to recover the first SoundTrap after a 10-month deployment (photo by Teresa Tomassoni).

Gerlache Strait, Antarctica — May 15, 2025 — In the icy heart of the Antarctic Peninsula, a new scientific effort is shedding light on the secret lives of whales. With funding from the Antarctic Wildlife Research Fund (AWR), a team of researchers has completed a successful expedition to the Gerlache Strait aboard HX Expeditions' MS Roald Amundsen, led by Dr Heidi Ahonen, a bioacoustician at the Norwegian Polar Institute (NPI). This initiative, conducted in partnership between the NPI and the Association of Responsible Krill harvesting companies (ARK), represents a major step toward understanding how whales use key foraging areas in a region shared with the krill fishery. The project was also suported by IMR (Norway) and IAATO.

Central to the project are three autonomous acoustic recorders known as SoundTraps. These compact devices ― named Hermione, Ron and Harry ― deployed at depths of up to 300 meters, record underwater sounds such as whale calls and other underwater sounds. Designed to operate for extended periods, each SoundTrap was moored to the seafloor in the Gerlache Strait/Bransfield Strait last year and recorded continuously for 10 months—from mid March to mid January.

The recovery of these long-deployed instruments during the recent cruise provides a full seasonal record of whale presence in one of the Southern Ocean’s most biologically rich corridors.

This work directly contributes to the science needed to inform precautionary, ecosystem-based management of the krill fishery under the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). As CCAMLR continues to refine a new management framework for krill, understanding predator use of foraging habitats has never been more important.

The successful expedition aboard the MS Roald Amundsen demonstrates the critical value of collaborative science. The vessel’s logistical capabilities allowed researchers to access remote mooring sites, conduct safe recoveries, and begin data analysis while still at sea. Heidi Ahonen emphasized the importance of collaboration between scientists and industry in advancing ecosystem-based management, stating, “There are only few research vessels operating regularly in this area, so partnering with HX Expeditions and using the MS Roald Amundsen was not only practical—it was essential to make this research possible.” At the same time as SoundTraps are recording vocal whales, the team has deployed marine mammal observers aboard the FV Antarctic Endurance, operated by Aker QRILL, to conduct visual surveys. Listening and counting are two complimentary ways of understanding how whales use this highly productive area. Typically, such visual surveys occur in the middle of the summer, but this scientific collaboration will extend whale monitoring during the fall and winter months when we are less certain how many of what species are present. This effort underscores the fishing industry's growing commitment to marine science, as Aker QRILL’s support enables researchers to gather crucial seasonal data on whale presence in actively harvested areas. 

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A sonogram of a humpback whale vocalization (source: Heidi Ahonen).

“This mission helps fill a key data gap in one of the most dynamic and sensitive areas of the Antarctic ecosystem,” said Javier Arata, Executive Officer of ARK. “By listening to the deep, we gain the insights needed to guide the sustainable use of krill while safeguarding the health and balance of the entire Antarctic ecosystem—from penguins to whales.”

The project exemplifies how transparent, science-based cooperation between research institutions and industry can deliver actionable knowledge for conservation. As whales recover from centuries of exploitation and face new pressures from climate change and resource use, efforts like these provide the foundation for sound stewardship of the Southern Ocean.

The recovery of the SoundTraps was made possible through the support of HX Expeditions and in collaboration with the Norwegian Polar Institute (photo by Leonard Stanley).

Locations of the three SoundTraps deployed in 2024. These sites include two distinct fishing grounds — ‘Ron’ in Bransfield Strait and ‘Hemione’ in northern Gerlache Strait — as well as one non-fishing, ‘Harry,’ in southern Gerlache Strait. ARK VRZs are noted in yellow.