New research suggests melting Arctic sea ice may be drawing more killer whales into northern oceans, raising concerns among Inuit hunters about increasing competition for food.
Federal researcher Jeff Higdon has compiled a database of the number of times the sleek, black-and-white predators have been spotted in the waters north of Newfoundland since the 1980s.
"There's been a massive increase," he said Thursday.
Two decades ago, hunters, scientists and other northern travellers usually reported about six killer whales a year in the waters of western Hudson Bay, he said. By 2000, the number of sightings in that one area had ballooned to more than 30 annually.
Higdon's data comes from Inuit hunters, conservation officers and ecotourism operators. While Arctic tourism has increased in recent years, most of the information comes from the relatively stable number of hunters who go out on the water.
The reason for the increase in killer whale numbers is unclear. But Higdon, who works with the Department of Fisheries and Oceans in Winnipeg, said his research shows a strong correlation between increased sightings and the decline of sea ice.
"For Hudson Bay at least, there's a direct relationship there. Declining sea ice is directly correlated to increasing killer whale reports.
"It's definitely a large impact."
Recent NASA studies suggest that climate change is causing Arctic sea ice to melt faster and faster.
For more than 25 years, winter sea ice diminished by about 1.5 per cent per decade. But in the last two years, melting has occurred at rates 10 to 15 times faster.
From 2004 to 2005, the amount of ice dropped 2.3 per cent and over the last year, it's declined by another 1.9 per cent.
A second NASA study found the winter sea ice in one region of the Eastern Arctic has shrunk about 40 per cent in just two years.
While the shrinking sea ice is creating major problems for animals such as the polar bears of Hudson Bay, it may be providing a smorgasboard for killer whales.
"We've got reports of killer whales attacking every marine mammal in the Arctic," Higdon said. Although there are no reports of a killer whale taking on a polar bear, there are records of them bringing down belugas, narwhals, walrus and even huge bowhead whales.
That concerns some Inuit hunters, who depend on the same animals to keep their larders stocked.
"They're a bit concerned that too many killer whales is not good for the whale population," said Gabriel Nirlungayuk, director of wildlife for Nunavut Tunngavik Inc., which administers the Nunavut land claim.
Some, however, appreciate how killer whales drive pods of narwhal closer to shore, making them easier pickings for humans, Nirlungayuk said.
There are still many unknowns about the Arctic killer whale population. There's even a chance that the increase in sightings may be the result of growing populations after the end of commercial whaling in the 1970s and has nothing to do with climate change.
But the federal government is now sponsoring research into the issue. Undersea microphones were mounted near Churchill, Man., and Repulse Bay, Nunavut, last summer to record whale cries.
Scientists are now poring over the tapes to separate out killer whales from the other animals, said Higdon. As well, hunters have been asked to report any sightings.
Meanwhile, hunters on the ocean are grateful they no longer venture forth in kayaks, said Nirlungayuk.
"If you're in a small kayak, a killer whale is not something you want to see," he said. "It was something to be feared.
"Today, we have big boats. It's an excitement more than fear."
