This information will help researchers monitor blue whale populations.
Scientists have completed a 15-year study on blue whales in the Antarctic, publishing their findings in a comprehensive sonic survey. Utilising passive acoustic devices called sonobuoys, researchers gathered nearly 3,900 hours of sound data, focusing on three distinct types of calls made by these elusive creatures.
The study, led by marine mammal acoustician Brian Miller from the Australian Antarctic Programme, sheds light on the distribution and behaviour of Antarctic blue whales, which were once hunted to near extinction during industrial whaling.
"This analysis represents the most contemporary circumpolar information on the distribution of these rarely sighted and elusive animals, which were hunted to the brink of extinction during industrial whaling," says Brian Miller.
"We can reliably listen for [these whales], sail to them and visually sight them, then photograph and follow them, and even take small biopsies of their skin and blubber for further study."
The analysis revealed three distinct calls, including the Z-call made exclusively by males, the Unit-A call unique to this region, and the 'social' D-call made by both male and female whales. These calls provide valuable insights into whale populations and behaviour.
While the exact meanings of these calls remain unclear, combining acoustic data with other methods such as drone footage and AI algorithms allows researchers to monitor whale movements and assess the potential impacts of climate change on blue whale populations and their main food source, krill.
The study, published in Frontiers in Marine Science, lays the groundwork for future research using passive acoustic monitoring to address knowledge gaps about Antarctic blue whales and their habitat.