If you spend some time on the banks of the St. Lawrence River in Quebec, you just might catch a flash of white beneath the surface. A whale. A beluga whale.
You don’t typically expect to find whales in a river, but, sure enough, whales swim here, year-round, in a river hundreds of miles from the open ocean. Small, ivory-colored beluga navigate the same freshwater corridors as cargo ships and kayaks. The story of Arctic whales making a home in a Canadian river doesn’t begin with water but with ice.
A sea that no longer exists
About 15,000 years ago, the enormous Wisconsin glacier that had covered much of North America began its slow retreat. As it melted, it left behind a profound geographical mark. The glacier’s weight compressed the land it sat on for millennia, inviting seawater from the Atlantic to flood the resulting low basin. A vast inland sea, the Champlain, stretched from the Atlantic coast westward toward the Great Lakes and what is now New York.
Whales, walruses, narwhals, humpbacks and seals all roamed in what would become the St. Lawrence lowlands. Their fossils have been found between Quebec City and the Ottawa Valley. Researchers have found the remains of porpoises, humpback whales, fin whales, bowhead whales, and multiple seal and walrus species buried under the sediment of what are now farms, fields and suburban lots. In 2001, the Université du Québec à Montréal recovered a beluga fossil more than 10,000 years old.
When the ice age ended, the land rebounded and the Champlain Sea drained. The St. Lawrence River remained, containing a population of belugas that stayed. As the glacier withdrew and dry land emerged, beluga whales took up residence in the estuary that formed. The population that stayed became genetically isolated from all other beluga groups in northern Canada, Russia and Alaska.
The St. Lawrence River is the only home their lineage has known for longer than recorded human history. Over thousands of years, they adapted. Their behaviors are in tune with the river’s rhythms. Their seasonal patterns are distinct from their Arctic counterparts. Having been present in the St. Lawrence River for 10,000 years, belugas have adapted to an extreme and changing environment. They play a role in their ecosystems. For many Indigenous communities, they have served as a subsistence resource as well as a source of food security and culture.
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A population under pressure
The St. Lawrence belugas are now listed as endangered. There were an estimated 10,000 whales at the turn of the 20th century, but now roughly 1,800 belugas remain. Recent surveys suggest the number may be closer to 900. The population was severely reduced by hunting, which continued until 1979. High contaminant loads, vessel traffic and industrialization of the surrounding watershed have prevented recovery even after hunting was restricted.
And now climate change is compounding the pressure from a direction these whales have never faced before: A warming Arctic is pushing new species into old territories. As climate change continues to warm the Arctic and reduce sea ice, orcas have been spotted in beluga whale habitats, introducing a major predator of all three Arctic whale species. Less ice means less refuge. More open water means more ship traffic, more noise and more disruption of the acoustic communication belugas depend on to feed and reproduce.
Every year around the third week of September, scientists at the National Snow and Ice Data Center announce the Arctic sea ice minimum, the point at which summer melt has reached its furthest extent before winter refreezing begins. The last 19 September extents, from 2007 to 2025, represent the 19 lowest on record. The trend line, measured across nearly five decades of satellite data, moves in only one direction.
For the St. Lawrence belugas, this number is extremely consequential. The glacier that created the Champlain Sea and stranded their ancestors in a river changed their world irrevocably. The warming that is now shrinking sea ice is doing the same thing, on a faster timeline than any glacier melt.
The St. Lawrence belugas aren’t the only beluga population in trouble. Cook Inlet belugas in Alaska are also endangered, and other Canadian populations are of serious conservation concern. Ocean Conservancy works to protect these distinct populations through support for ecosystems and biodiversity. Groups of belugas in places like the St. Lawrence River and the Arctic have been separated for such long periods that they highlight the importance of genetic diversity when it comes to climate resilience. Losing one species, like the St. Lawrence population, cannot simply be offset with lots of belugas in another part of our world. They represent thousands of years of history and adaptation.
The beluga in the St. Lawrence is a living record of what the ocean once was and a signal of what it is becoming. Our ocean shapes life in ways that travel further inland and last far longer than we expect.
Chart a New Course for Whales
The Whale CHARTS Act would reduce ship strikes by amending NOAA’s near-real-time monitoring and mitigation program for large cetaceans to improve our understanding of the location and extent of baleen and sperm whale migration routes and feeding, mating and calving grounds.
