Killer Whale Sightings Increase In Arctic

Friday, January 12, 2007
NUNAVUT - As the Arctic sea ice shrinks, the number of killer whales spotted in Arctic waters has dramatically increased over the past six years.

That could be bad news for anyone who enjoys the taste of beluga, narwhal or bowhead whales. That’s because killer whales love eating these sea mammals, too, and they have quite the appetite, consuming on average more than 226 kilograms of food a day.

In particular, the number of killer whale sightings in the Hudson Bay has increased to 30 over the last six years, compared to only six sightings throughout the entire 1990s.

The 1980s only had six sightings as well. Before then, reported sightings per decade were even lower.

These figures come from research conducted by a group called Orcas in the Canadian Arctic, which began in September 2005, as a collaboration between researchers from University of Manitoba, the federal Department of Fisheries and Oceans, and the Government of Nunavut.

It’s not clear if killer whale populations are increasing, or if the whales are simply moving to new locations, says Jeff Higdon, a PhD student with the University of Manitoba who is involved with the project.

But a relationship does seem to exist between shrinking sea ice levels in the Hudson Strait, and a big increase in the number of killer whale sightings in Hudson Bay.

“The relationship is certainly there, and it does make sense,” Higdon said on Tuesday.

Higdon said he spoke with Inuit hunters who are worried that killer whales are growing in numbers, and competing with hunters for food.

A hunter in Pond Inlet told Higdon he’d never seen as many killer whales as he did last summer.

Higdon cautions the study right now is “not terribly scientific,” because it’s only based on whale sightings. That means it’s anyone’s guess how many other whales go unsighted, or unreported.

Higdon is asking for more reports of sightings from Inuit hunters, who he calls the real killer whale experts.

“These are the guys who know,” Higdon said. “When they tell me there are more and more killer whales, I believe them.”

Killer whale sighting forms have been distributed to hunter and trapper association offices across Nunavut, Higdon said. He asks anyone who sees a whale to report it.

In the future, Higdon would like to see a more extensive study, such as has been done on Canada’s west coast, where an extensive killer whale database has been built up over the last 30 years. This allows researchers to identify individual whales based on the markings on their dorsal fins and white “saddle patches” behind the fin.

Killer whales were never seen in Repulse Bay before the 1940s, according to historical research done by Higdon.

During Knud Rasmussen’s fifth Thule expedition, from 1921 to 1924, Magnus Degerbol and Peter Freuchen reported that Inuit near Repulse Bay had not seen killer whales, but had heard of them from others who lived further east.

At that time, Inuit told the researchers they believed killer whales did not travel through Hudson Strait because walrus in the area scared them off.

The researchers suspected otherwise: they believed sea ice in the strait prevented whales from passing into Hudson Bay.

That’s not to say Inuit did not predict this would happen. They did.

During his research, Higdon heard a story of an elder in Repulse Bay during the 1940s who, before he died, predicted that residents would see a new kind of whale.

Sure enough, within two years, the first killer whale was sighted in the area.

And now, killer whales are spotted off Repulse Bay every summer, Higdon said. “We could call it a hot spot.”

Much remains to be learned of killer whales in the Arctic. For example, “we have no idea where they go in the winter,” Higdon said.

It’s also unclear how many killer whales live in the Arctic, and how many different populations exist. On Canada’s west coast, killer whales are divided between resident populations, which stay in one area year-round and primarily feed on fish, and transient populations, which migrate to different areas and feed on marine mammals such as seals.

Genetic research shows resident and transient killer whales have not interbred for some 10,000 years.

Whether such a division exists between Arctic killer whales is yet another unanswered question.

It’s commonly suggested that killer whales don’t usually venture near pack ice in the Arctic because of their prominent dorsal fins, which can stand one and a half metres tall.

But in the Antarctic, killer whales do travel beneath the ice pack, following leads for kilometres and breathing air pockets beneath the ice, as beluga do in the Arctic.

Why killer whales don’t appear to do the same in the Arctic is yet another mystery.

It’s possible that killer whale populations have rebounded since the end of commercial whaling in Canada in 1970. Whalers considered killer whales a pest, and would often shoot them on sight.

Killer whales are usually not well-loved by Inuit hunters. Perhaps that’s because they share the same tastes for food.

But Higdon has heard some hunters cheer killer whales. That’s because the whales will drive their prey towards shore, making other animals easier to shoot.

Source: Nunatsiaq News