Canada finds killer whales drawn to warmer Arctic

TORONTO (Reuters) - Melting Arctic sea ice may be attracting more killer whales to Canada’s far northern waters, and that could mean some Inuit hunters will be competing directly with the majestic marine mammals for food, a group of researchers say.

“For a number of years, Inuit hunters in the eastern Arctic have been reporting that the number of killer whales is increasing,” Jeff Higdon, a graduate student at the University of Manitoba, working with the federal Department of Fisheries and Oceans, said on Friday.

“Of course the killer whales that are in the Arctic are eating a lot of the same marine mammals that Inuit hunters depend on.”

Killer whales, or orcas, are the biggest members of the dolphin family and are found around the world. They are often seen in Canadian waters, though they are not as common in the far north.

The latest data compiled by Higdon and other researchers, who began researching the whales in September 2005, tracks the number of times they are spotted in the waters of Hudson Bay, against declining levels of sea ice.

In the 1980s and 1990s, Higdon said hunters, scientists and others living in the north reported six sightings each decade in the waters of western Hudson Bay. The number of sightings of killer whales reported in that area has now grown to more than 30 over the past six years, said Higdon.

“What we found was there was a significant correlation between the fact that the ice was declining in Hudson Strait and the number of killer whales were increasing.”

The data come from Inuit hunters, scientists, conservation officers and ecotourism operators, among other sources, said Higdon. But he added the numbers are not exact science since many more orcas may exist in the region, but are not reported.

The current levels of Arctic sea ice are the lowest they’ve been for the past few centuries, recent NASA research suggests. For nearly 30 years, winter sea ice diminished by about 1.5 per cent per decade. In the past two years, it has fallen by 6 percent each year.

While the reason for the increase in the whale numbers remains unclear, scientists and Inuit hunters are eager to understand why more orcas are showing up, said Gabriel Nirlungayuk, director of wildlife for Nunavut Tunngavik Inc.

“The elders say they have always seen orcas coming to their waters to feed,” he said. “But for the past three years they are noticing the orcas are sticking around in their waters more so than would have in the past.

That triggered more research efforts by the federal Fisheries Department, said Nirlungayuk.

The longer range plan is to help manage the orcas’ bigger prey such as the beluga, narwhal and bowhead whales, said Steven Ferguson, a research scientist with the Fisheries Department and leader of the project.

The black-and-while animals are efficient predators that can grow about 9 meters (30 feet) in length and weigh more than 7 metric tons.

“If the northern hunters are expecting these animals to be there for them for their subsistence hunt, and killer whales are hunting the same whales, it could be a problem,” said Ferguson.

Currently, undersea recorders are in place near Repulse Bay, Nunavut, and Churchill, Manitoba, on the western shores of Hudson Bay, in order to track sound and movement, he added.

Changes such as the disappearing sea ice have the long-term potential of changing entire ecosystems, Higdon added.

“It may be a sign of things to come in the Arctic,” he said.