Temporal segregation of the Australian and Antarctic blue whale call types (Balaenoptera musculus spp)
To our surprise, not all Antarctic blue whales return to the Antarctic to feed in the austral summer - their vocalizations are detected year-round in mid and low latitude northern waters – as far north as the Lau Basin.
BLUE WHALE VOCALISATIONS REVEAL POPULATION STRUCTURE
We eavesdrop on singing whales, the Antarctic blue whale and other sub-species, detecting their vocalizations in continuous multi-year (over 16-years at some sites) acoustic recordings at sites across the southern Pacific, Atlantic and Indian oceans. We use different arrays, including the world-wide network of underwater hydrophones that listen for nuclear explosions (the UN General Assembly CTBT Nuclear Test Ban Treaty system). It is poetic that infrastructure developed to prevent nuclear warfare is perfect to answer questions about the acoustic behaviour of one of the world’s most secretive mammals – the blue whales.
We have found that there are different populations of dialect-speaking pygmy blue whales off the eastern and western Australian coastlines. The pygmy blue whales migrating along the East coast of Australia have a ‘Kiwi’ (New Zealand dialect), not Australian ‘accent’ – to the delight of our Kiwi colleagues.
Illustration by Danielle Clarkson