Climate change is shrinking Arctic ice, which is increasing human marine activity and underwater noise. To protect sound-sensitive marine life—from marine mammals to tiny crab larvae—scientists are calling for proactive, evidence-based guidelines that set safe acoustic limits for seasonally ice-covered waters.
Using a decade of hydrophone data (2015 to 2024) from the Ocean Networks Canada (ONC) coastal community observatory at Cambridge Bay, Nunavut, a research team led by Philippe Blondel, a senior lecturer in the Department of Physics at the University of Bath, in England, analyzed subsea noise from human activity. The hydrophone is situated 13 metres below the surface in Cambridge Bay and is part of ONC’s network of acoustic monitors on the three coasts of Canada.
In a 2026 paper in the Nature journal NPJ Acoustics, Blondel noted that Arctic Ocean noise will likely increase as ice recedes more and transport passages open up, bringing more shipping, cruise ship activity spikes, and pressure for the expansion of mining and drilling.
Blondel and colleagues focused their research on the months of May (full ice cover, no shipping) and August (limited or zero ice, more shipping activity) and found differences in underwater sounds. Blondel says his interest is in “loud sounds, anything louder than the background noise” of cracking ice and animal vocalizations (more than 10 decibels).
Many sounds come from smaller ocean-going vessels, which aren’t required to carry automatic identification system (AIS) transponders, in addition to snowmobiles (in winter), machinery near the shore or on ships, and even overhead aircraft. In summer, these loud sounds extended to frequencies well above 1 kHz, up to tens of kHz in cases, whereas they remained below 1 kHz at the maximum extent of ice cover.
Sound identification
In general, the number of ships heard is much larger than the numbers of ships tracked by AIS. Aural identification of the different sounds in May and August 2018, showing the mean sound levels (lines), percentiles (points for each third-octave band) and individual events identified (for example 1966 snowmobile recordings in May). Source.
In an article about the research in theconversation.com Blondel says that “like shipping, these sounds should also be part of monitoring and regulating underwater noise in the region”. Furthermore, “modelling sound impacts from satellite tracking is an insufficient way to gauge how much noise human activity is generating… underwater noise must be based on actual measurements in the field.”
Audio provided by Philippe Blondel.
Acoustic data to support marine regulations
Blondel says regulations typically focus on frequency bands associated with large ships, with the European Marine Strategy Framework Directive often seen as a model, but monitoring is a critical piece of the puzzle.
“Canada and other Arctic countries are ideally placed to collect the evidence that can define an Arctic marine strategy framework directive. This becomes more urgent as the climate changes, the Arctic opens to human activities and pressures on Arctic resources grow."
Blondel suggests that the ONC-aided research can provide a baseline for governments to monitor vessel noise at different frequencies in the Arctic to protect marine life and communities that depend on hunting and fishing.
He also notes the projected effects of climate change, saying, “There will be changes because the ice is melting, the ice season is going to be completely different. There will be more ships able to go to these places. The biodiversity is going to change as so many animals move around to get to colder water.”
Those creatures will also move to avoid that noise disturbing their feeding, navigation and socialization practices.
Marine mammals are sensitive to noise
“Because the Arctic is melting and is changing nearly four times faster than anywhere else on the planet, it affects the ecosystem, it affects the animals that live there,” says Lyne Morissette, a Quebec-based marine biologist who serves on the ONC board of directors. “And we need as much data and knowledge as possible to better understand it because it's changing fast.”
She notes that different sounds at different wavelengths have different effects on animals: A variety of marine mammals might decrease foraging and socializing. Humpback whales might increase how much and how loud they vocalize. Beluga and narwhal pods might move faster and less predictably. Seals, which spend part of their time in the ocean, part on ice, which they need to breed, can be displaced from ice haul-outs by airborne noise, potentially disrupting reproduction and affecting their survival.
Changes in marine species behaviour also affect communities that depend on hunting and fishing to live.
“Marine mammals are highly sensitive to noise and they are acoustic animals,” Morissette explains. “Of the five senses that they have, hearing is the most developed. So sound for them is the most important thing.”
Beluga whales swimming in an Arctic crack of broken ice shelf, aerial shot.
Adaptation can’t keep up with noise increases
ONC acoustic specialist Lynn Rannankari notes that marine mammals’ behaviour is based on generations of adaptation “but if you're increasing vessel noise over, say, five years, they can't adapt to that.” The bioacoustician also notes marine mammals’ behaviour is based on generations of adaptation “but if you're increasing vessel noise over, say, five years, they can't adapt to that.”
“So, basically, their options are to endure it, which can create stress in their lives and can affect their ability to find food, to find each other, to find mates. And oftentimes what you see is that whales will actually be displaced out of the area,” Rannankari says.
Lanfranco Muzi, an ONC senior scientist who specializes in physical acoustics, or how sound moves through water and interacts with the environment, says more attention has been paid over the last couple of decades to noise “as a form of pollution” as research asks, “What does it do to the animals?”
Rare opportunity to establish baseline for marine noise
Muzi points out that long time-series data produced by ONC’s monitoring stations on the Pacific, Atlantic and Arctic coasts of Canada, helps researchers better understand ocean soundscapes so they can aid authorities in developing policy and practices to reduce human impacts on marine species.
And because of the availability of that data, Rannankari says:
“We have this rare opportunity to be proactive in protecting Arctic marine life before human activity reaches levels seen in other ocean regions. Long-term acoustic monitoring provides the capacity to start analyzing changes and creating a baseline for those noise levels.”
This speaks to the value of the data ONC and its community partners collect, Muzi adds, saying that research could provide the basis for, say, moving a shipping lane or regulating ship speeds to limit marine noise.
Blondel says the data provided by ONC—and, especially, that it’s openly available on the Oceans 3.0 Data Portal—are integral to his work and critical to monitoring marine noise. As he wrote in his theconversation.com article, "ONC’s Ocean Data Portal is a dream come true for scientists: 64,000 sound measurements per second, for years on end, complemented in season with local ice profiling,” adding researchers also used local weather data from Nav Canada, satellite charts of regional ice cover from the Canadian Ice Service and ship tracks from the Arctic Council’s Arctic Ship Traffic Database..
He also lauds ONC for engaging with the people who live in Cambridge Bay, where the monitoring stations are, saying, “I like their community involvement both on the west coast and in the Arctic. It’s really talking to the people who own the land, who live on it.
“Thanks to Ocean Networks Canada, I was able to talk to the people of the Hunters and Trappers Association, and it was very interesting because I could hear from them why they care about underwater sound, or why they don’t, and how these measurements can help them directly.”
ONC engineers Albert Ruskey and Caleb Magee install an acoustic receiver, used for studying the movement and behaviour of aquatic animals, onto a hydrophone tripod within the Cambridge Bay coastal community observatory. Credit: Brodie Larocque (POLAR-POLAIRE)
An initiative of the University of Victoria and one of Canada’s Major Research Facilities, ONC operates world-leading observatories in the deep ocean and coastal waters of the Pacific, Atlantic and Arctic coasts of Canada as well as the Southern Ocean. The ocean data collected accelerates scientific discovery and makes possible services and solutions for a resilient planet.
Header image: Philippe Blondel collecting hydrophone measurements in an ice-laden fjord deep in Svalbard, 2014. Credit: Prof. Jaroslaw Tegowski, University of Gdansk. Picture background extended with AI to fit dimensions.
