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Arctic shipping: Studying underwater noise in Northwest Passage

CBC NewsEye on the Arctic
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A group of U.S.-based researchers wants to record underwater noise levels in the Northwest Passage near the community of Resolute, in Canada's eastern Arctic territory of Nunavut, to track changes that may come with increasing ship traffic. Philip Manik, chair of the local hunters and trappers organization, says ship traffic is already having a noticeable effect on wildlife.

"Any amount of disturbance increases will have an effect on marine mammals, either their migration routes, or where they have haul-outs," he said.

John Hildebrand of the University of California is leading the project.

"You know, when the ice forms, the Arctic is one of the most quiet environments on the planet," he said. "I think that the animals are probably pretty adapted to having a quiet setting."

Hildebrand said that as the open-water season gets longer, the submarine environment may become noisier.

He points to areas off the California coast, where heavy shipping traffic has increased the ambient noise underwater by 20 to 30 decibels.

"We're still learning what the effects are of human-made sound on marine mammals, it's not all worked out," he said. "For high levels you worry about injury, and for low levels you worry about disruption, disturbance."

The plan for the Northwest Passage is simple — sink a microphone to the seafloor in the Barrow Strait off Resolute, press record, and come back a year later. Then repeat for several years.

The researchers will then analyze the recordings, to identify animal sounds — from whales, seals or walrus — and other contributors to underwater noise.

"We're hoping to make a record of what is the sound level in the absence of the ships," he said. "Then 20 years from now, if there are more ships going through, we know how things have changed."

Hildebrand said the recording equipment has already been shipped to Resolute. He's waiting for the go-ahead from Nunavut regulators to anchor his microphone before the ice forms.