With a warmer climate, the sea ice is melting and more species are moving to northern latitudes. For killer whales, the melting sea ice provides new roaming opportunities further north into the Arctic Ocean.
– Areas previously inaccessible to killer whales have opened up as they are no longer covered by ice. – Killer whales have always moved between different areas, but they are now increasingly seen in the Arctic, says Hanne Strager, biologist and whale researcher.
But killer whales moving into new territories is not without consequence and could affect the region’s ecosystem. The melting ice may also pose a risk. For example, some groups use the ice to hunt seals. By jumping onto the ice, they knock the seal into the water, making it easier to hunt. But when the ice melts, their specialized hunting technique could be prevented, limiting their access to food. Some seal species may also decrease in number when they can no longer seek shelter on the ice.
– But other species, such as beluga whales and narwhals, may also decline in numbers if killer whales hunt in waters where they are present. In addition, the ice-free regions may mean that the whales themselves end up in waters where whale hunting is allowed, says Hanne Strager.
Climate change requires genetic diversity
For a species to survive, there needs to be a genetic diversity. Diversity contributes to a wider range of traits and is particularly important when conditions change.
Genetic isolation, on the other hand, means that a population has few genetic differences. Researchers at the University of Manitoba in Canada studied two small groups of killer whales living in the Artic. According to their study, published in the scientific journal Global Change Biology, they found that the groups are genetically isolated. But also that they have declined in numbers.
Hanne Strager believes that the genetic isolation of killer whales is problematic.
– When there are few genetic differences, it is more difficult for species to adapt. This makes them more vulnerable, particularly to temperature differences or changes in food. When groups are small, there is also a high risk of inbreeding, which further reduces the genetic diversity.
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