Underwater recorders have helped scientists learn more about whale life. From their singing, biologists realized that the whales had abandoned their traditional migration to the south and remained in place.
Records collected during the winter of 2018-2019 in the icy waters of the Arctic off the coast of Canada proved that the bowhead whale population missed their usual southward migration.
Scientists believe this behavior – never seen before – is caused by the effects of climate change. Scientists also consider this a potential harbinger of changes in dynamics in the ecosystem of the region.
Usually, from 17 to 20 thousand individuals that make up the Bering-Chukchi-Beaufort (BCB) population have a fairly predictable migration pattern, covering 6,000 km. They spend the winter in the part of the Bering Sea between Russia and Alaska, head north in summer, then east to the Beaufort Sea and Canadian Amundsen Bay, and return in the fall.
But in the winter of 2018-2019, the situation has changed. Residents of the Canadian region reported seeing Greenlanders at a time when they should have been in the south. A team of scientists decided to examine the sounds recorded by underwater devices scattered throughout the region to regularly collect data and listen to whales singing. The observations of local residents were confirmed. It turned out that the characteristic songs of bowhead whales, which should have been already in the southern winter territories at that time, remained in place.
“The evidence is clear that Greenlanders hibernated in the summer feeding area in the eastern Beaufort Sea and Amundsen Bay during the winter of 2018-2019. And, as far as we know, this is the first time this has been reported, ”says an article in the Royal Society Open Science.
However, it is not entirely clear why this happened. The authors put forward various theories, mainly related to climate change.
One of the possible factors could be the displacement of the ice cover when there was much less ice on the summer territories in the winter season 2018-2019 than usual.
Another possible explanation is “predator avoidance.” Bowhead whales stay away from killer whales, which are increasingly seen in some unusual habitats. The fact is that the warming of the seas leads to a decrease in the ice cover and an expansion of the halo of their habitat.