For Alex Otuvac, watching spotted gray narwhals migrate across the icy waters of the Arctic during hunting season is a fond childhood memory.
“It felt like a never-ending, loop-over view of whales, constantly swimming past you in the same direction, all migrating throughout the day, sometimes for more than a day,” said Oootuwak, who lives in Mittematalik, also known as Pond Inlet, in Canada’s far north. “You’re always taught to be extra, extra quiet and careful […] Because they’re very sensitive.”
The world’s more than 80,000 narwhals live primarily in northeastern Canada and Greenland. For the Otuwak and other Inuit communities in Canada, narwhal meat has been key to their survival for at least 1,000 years. It is an important source of protein, iron and vitamin C and hunting is regulated by the government.
“This is our way to stay healthy and stay connected to our land and our culture,” Ootuwak told DW. “This is not something we do just to kill animals and take them for sport.”
Narwhal numbers are declining
But Ootuwak hasn’t seen a childhood-like migration for a long time. Over the past 20 years, hunters have noticed that whales have become thinner and harder to catch. As of 2021, only about 2,000 remained in the region – a 90% decline from more than 20,000 in the early 2000s.
It’s not clear why the whales are disappearing, and what’s driving them away. Researchers suspect that climate change may play a role, with the Arctic region warming four times faster than the rest of the planet.
“A lot of things are changing – not just ice, water temperatures, species, from the bottom to the top of the food chain,” said Kristin Westdahl, a marine mammal specialist with the Canadian marine conservation network Oceans North.
But he said the effects of climate change are gradual and the decline in whale populations has occurred over a relatively short period of time. “And the only thing that changed that habitat so rapidly was the amount of ships coming and going.”
In 2015, a local mine operated by a company called Baffinland opened a port nearby. Within two years, approximately 4 million tons of iron ore was shipped through the waters of Mittamtalik – and noise pollution increased dramatically.
Noise pollution is driving away whales
Concerned about what the new noise was doing to the narwhals, Ootuwak and Westdahl set up two listening stations in Milne Inlet, west of Mittematalik. Within a few years, they were able to expand their acoustic monitoring program by collaborating with acoustics experts at the Scripps Institution of Oceanography in San Diego.
By lowering special microphones called hydrophones through holes in the ice and 800 meters (about half a mile) below the water, they have listened to the Arctic seascape 24/7 – to marine life such as seals barking and narwhals clicking in search of food, but also the rumble of engines caused by increasing ship traffic. And they have found that these ship noises may be behind the decline in narwhal numbers.
monitoring team Published a study in 2025 which found that “narwhals either move away or stop vocalizing” when ships come within 12 to 24 miles (20 to 40 kilometres). And the whales were responding to noises below the 120 decibel threshold – like loud thunder, or roaring chain saws – which is considered the disturbance threshold for medium-sized whales like narwhals.
Hunters have also noticed that narwhals begin to behave differently when a ship is nearby.
“As soon as the ship starts its engines, they move away or stop feeding, diving deep, where they’re feeding on fish on the ocean floor,” Ootuwak said. Whales have learned to avoid heavily traveled shipping channels when there are boats in the area, he said.
Are narwhals headed to Greenland?
Otuwak said it’s not clear where the whales were going, but he has a theory. On a trip to northern Greenland in 2024, across Baffin Bay to the east – where narwhals typically spend the summer months – they spoke to local hunters who told them about whales that had begun to appear in their waters, just as shipping from Mtimtalik increased.
“They called the narwhals ‘foreign’ because they were long and thin and their behavior was so different from that of their narwhals,” Ootuwak said. He told that hunters say that whales are easy to hunt and their taste is also different.
Outi Tervo, senior scientist at the Greenland Institute of Natural Resources, is also researching narwhals and noise pollution. He has observed that noise from shipping and air gun pulses from oil and gas exploration can cause narwhals to stop searching for food, which is consistent with Ootuwak’s observation of seeing thinner narwhals.
Tervo said he has seen no evidence that whales have moved from Canada to Greenland, but said an increase in unfamiliar sounds could prompt them to migrate.
For narwhals that rely on echolocation for communication and hunting, he said the ability to hear is what the ability to see is to humans. So just as bright headlights or a flashlight pointed at the eyes temporarily blinds us humans, sounds that interfere with narwhal echolocation profoundly disrupt their activity and prompt them to be “ready to flee,” she said.
Tervo said habitats for narwhals are limited, and they have adapted to life in the Arctic. “They can’t swim to the Caribbean and spend the winter there,” he said. “So I think it’s very important to take into account the needs of animals and try to create some safe havens for them.”
Noise a growing concern as Arctic opens up
The good news, however, is that the noise monitoring project led by Ottuwak and Westdahl has raised awareness of noise pollution in the Canadian Arctic.
The local mining company, Baffinland, has reduced its shipping speed to 9 knots and is using fixed routes. Strict rules for when icebreakers can be deployed have also been agreed. Cruise ships are also increasingly coming on board, agreeing to speed limits and no-go zones.
“I would say it’s generally positive,” Ootuwak said, pointing out that the 2025 hunt was the first time in a decade that people were happy with what they caught during the fall migration. “It’s going to take some time, working with industry, working with government, to move these things forward in policy.”
Vestdahl said stronger monitoring, collaboration with local communities and much more data will be key to keeping noise pollution under control, especially as companies eye the increasingly ice-free waters of the Northwest Passage for international shipping.
“We’re seeing a slow and steady growth of people showing interest and trying to go there, whether it’s cruise ships, pleasure ships or occasionally commercial ships,” he said. “And I think having policies and regulations in place in the Arctic will be really important moving forward.”
This article was based on an episode of The Living Planet Produced by Kathleen Schuster.
Edited by: Sarah Stephan