The study claims that the Arctic is the fastest warming region on the planet and that, as sea ice retreats, its waters are becoming the ideal habitat for traditionally subarctic species such as killer whales.
Killer whales are expanding their territory and migrating to Arctic waters as climate change melts sea ice. Canadian scientists have identified two genetically distinct populations.
However, the study notes that this situation could have serious consequences for whales that are potential prey for killer whales, such as beluga whales, narwhals and boreal whales, species that lead researcher Colin Garroway described as slow, plump and delicious.
Complex situation
Garroway, an evolutionary geneticist at the University of Manitoba, said the situation is complex: Arctic killer whales have the potential to disrupt ecosystems because they are top predators, yet they deserve to be preserved.
The study indicates that killer whales could also affect humans, adding downward pressure on Arctic food webs essential to the social and economic well-being of northern communities.
The research notes that killer whales in the eastern Canadian Arctic have been observed to feed primarily on beluga whales and narwhals, followed by boreal whales and seals. We think there will be a big change in the community structure and the way these different species interact, Garroway said.
Fastest warming region on the planet
The study says the Arctic is the fastest warming region on the planet and, as sea ice retreats, its waters are becoming the ideal habitat for traditionally subarctic species such as killer whales.
University of Manitoba evolutionary geneticist Colin Garroway said that in the past, killer whales were considered rare visitors to Arctic waters because they risked breaking their famous dorsal fins when they collided with the thick ice sheets that once covered a greater expanse of those waters. But sightings of the killer whales in Arctic waters have become more frequent.
Garroway said researchers took tissue samples from the killer whales and were shocked to discover that there were actually two very distinct killer whale populations.
I couldn’t believe it and then I investigated and did some digging, which is pretty easy to do when you have the data. And sure enough, there were two distinct populations, Garroway said, adding that they numbered in the hundreds.
The study, published in June in Global Change Biology, describes one group as genetically distinct globally , while the second is similar to Greenland killer whales.
Garroway said the two groups of Arctic killer whales have different feeding behaviors and vocalizations and do not recognize each other as potential mates. Arctic killer whales are home to hundreds of thousands of beluga whales, narwhals, boreal whales, sperm whales and beaked whales, he said.
The Arctic is home to all those slow, fat, delicious whales that are easier to catch. It’s interesting to see more killer whales in the Arctic and how, being top predators, they can disrupt the ecosystem, he added.
The study highlights that killer whale prey species are culturally and economically important to indigenous communities; therefore, these species also deserve to be preserved and managed, considering the migration of killer whale populations into the Arctic.
Garroway said that during the multi-year research period, the team heard northern indigenous people express concern about the presence of migrating killer whales hunting for food that is crucial to their communities. That’s what makes the situation so confusing, because the orcas themselves are an endangered population and everything is changing , Garroway said.
Garroway said research was ongoing and little was still known about the ecology of Arctic killer whales, including where they go during the winter when the seas freeze over. Tracking them was difficult, he added.
We’ve had several killer whales with transmitters on, but the one that goes the farthest seems to take us to the edge of the Arctic and then turns off , Garroway said. We don’t know where these whales go when they are not in the Arctic, there is a lot to learn, the researcher added.
