Wednesday, 1 February 2012

Inuit traditional knowledge reveals steady migration of killer whales into Nunavut

Researchers from the University of Manitoba say they have better insight into the behaviour and diet of Canadian Arctic killer whales, thanks to traditional Inuit knowledge.

New research published in the online journal Aquatic Biosystems reveals new details about the species, based on interviews with Inuit hunters and elders from 11 Nunavut communities.

The study shows that melting sea ice is attracting more killer whales, or orca, to Nunavut, where the whales are preying on mammals like seals, belugas, narwhals and even the much larger bowhead whale.

And Inuit hunters are concerned that, as the sea ice continues to melt, they will have to compete with the giant predators for the marine wildlife they hunt for food.

Inuit hunters reported that killer whales “eat whatever they can catch”: mainly other marine mammals including seals (ringed, harp, bearded, and hooded) and whales (narwhal, beluga and bowhead).

There is little evidence to suggest that killer whales eat fish, hunters say.

Instead, Inuit referred to killer whales as “the wolves of the sea,” describing the animals as cooperative pack hunters who can kill by circling and herding single or groups of large sea animals.

Several hunters reported seeing bowhead whales “rammed” to death by a group of much smaller killer whales.

Other hunters said it was common to see killer whales tear into narwhal and “play soccer” with the mammal’s different parts.

The interviews, conducted with 105 Nunavummiut from communities along Hudson Bay and on Baffin Island, also revealed the intelligence and methodology used by killer whales in their hunt: many reported seeing the whales use their tails to create turbulence around ice floes in order to knock entire groups of seals into the water.

Many Inuit also described the predators as picky eaters, selecting only their favourite parts of the prey to eat and leaving behind other pieces, which were sometimes collected by Inuit hunters.

Inuit referred to prey behaviour as aarlungyuk, or the fear of killer whales, when smaller mammals seek refuge from the predator whale in shallow waters.

Even narwhal, which can stab killer whales with their tusks, were reported to have fled to shallow waters until the waiting predator gave up.

The study’s lead research, Dr. Steven Ferguson, said the traditional knowledge has now given researchers a better understanding of the effects of global warming and the loss of sea ice on Arctic species.

While killer whales have been studied extensively in the northeast Pacific ocean, little is known about the animal’s behaviour and prey preference in the Canadian Arctic, although the federal department of fisheries and oceans has documented increased sightings in recent years.

See the complete study here.

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