A long-term analysis of blue and fin whale vocalisations in the eastern Fram Strait has provided valuable insights into their seasonal and annual occurrence. Blue whales, the largest animals on Earth, are primarily heard during summer and autumn, while fin whales exhibit more variable and extended vocalisation periods. Remarkably, the dataset also confirms sporadic blue whale calls during winter months. The findings, led by the Alfred Wegener Institute (AWI) and recently published in PLOS ONE, offer a deeper understanding of these species‘ behaviours.
Climate Change Impacts and Habitat Shifts
The Fram Strait, heavily impacted by climate change, is experiencing rising water temperatures, declining sea ice, and shifts in the food web. For migratory baleen whales, the region is critical, as warm ocean currents enhance biological productivity. Since 2014, the AWI has operated the FRAM (Frontiers in Arctic Marine Monitoring) system here, using hydrophones to collect data on whale vocalisations.
“Progressing changes in the habitat, such as the loss of sea ice, will likely have substantial impacts on the occurrence of marine mammals,” explains Marlene Meister, a doctoral candidate and first author of the study.
The research predicts that blue and fin whales may extend their stays in the Fram Strait or potentially remain year-round.
Conservation Amid Climate Challenges
Fin whales demonstrated year-round vocalisations, reflecting their migratory flexibility, while blue whale calls were unexpectedly recorded in January and February during three out of ten studied years.
“Their sporadic acoustic occurrence in winter indicates that individual specimens extend their seasonal stay or return from farther south,” notes Meister.
This behaviour challenges previous assumptions about their migration stability. As sea ice declines, the Arctic is becoming more accessible to human activity, increasing stress on marine mammals from ship noise, habitat destruction, and other hazards. Long-term passive acoustic monitoring (PAM) through FRAM will remain crucial for tracking these changes and informing protective measures.
Originalpublikation: A multi-year analysis of acoustic occurrence and habitat use of blue and fin whales in eastern and central Fram Strait | PLOS ONE
