Increasing ocean temperatures caused by climate change will result in substantial loss of habitat for Arctic whales by the end of this century, a recent study predicts.
The study, published by the Greenland Institute of Natural Resources, found that the warming ocean could push the southern limits of Arctic whales’ distribution areas about 250 kilometres north in summer and roughly 125 kilometres north in winter by 2100.
“Their habitat is changing, and quickly,” said Kristin Westdal, science director for Oceans North. “And this study doesn’t take into account the human impacts as well—which only increase the pressure.”
Melting sea ice has allowed increased access for human pursuits such as commercial shipping, seismic surveys and mining operations, all of which cause noise and pollution and add additional stressors to the marine environment.
The study tracked 277 whales, from bowhead to narwhal and belugas, over a 28-year period up to 2020. Data from satellite tags was used to assess shifts in their habitat in the waters off western and eastern Greenland. These findings were then combined with climate models from the same time periods, including data such as sea surface temperatures. Based on this information, the study predicted that all three types of whales will lose substantial summer habitat in the coming decades.
Climate change has a big impact on narwhal because of their reliance on sea ice, limited range, specialized diets and other factors. These whales currently spend most of their summers in the waters north of Baffin Island, habitat that is expected to become inhospitable to this species over this century.
The study said that belugas could also be at high risk because they have a strong loyalty to their summer habitat and might be slow to adapt.
At the same time, species that roam between temperate southern waters and the Arctic, such as killer whales, humpback whales and harbour porpoises, could flourish in warmer oceans and move north. That would cause more competition for food and could result in increased predation on Arctic whales.
For northern communities that have traditionally relied on marine mammals for food, the loss of habitat is a big concern. Residents of Baffin Island hamlets like Pond Inlet and Pangnirtung have reported fewer sightings of narwhal in recent summers.
“The implications are serious for subsistence harvesting,” Westdal said.
For almost a decade, Oceans North has been studying the effects that increased shipping noise from Baffinland’s iron ore mine in Mary River are having on narwhal in Eclipse Sound. The acoustic monitoring research has already documented a substantial jump in underwater noise from the mine’s commercial ships at levels known to disturb narwhal and other marine mammals. Narwhal rely on pulsed and whistle calls to communicate with each other, and noise from ships like bulk carriers can mask the whales’ sounds by over 90 percent at less than five kilometres.
When such stressors are combined with the habitat loss predicted by the Greenland study, the future is uncertain for Arctic whales, she said.
“Taken together, we don’t really know what will happen to these species,” she said. “But we’re working hard to understand the implications of human activities in the Arctic and help communities address their concerns.”
Ruth Teichroeb is a regular contributor to Oceans North and former communications director. She is based in Seattle, Washington.