Two great white sharks were detected in the Gulf of St. Lawrence this week after travelling all the way up the east coast of the United States.
The sharks started their seven-month journey near Jacksonville, Florida and made their way into the gulf through the Cabot Strait on July 14, according to Ocearch, a non-profit organization that tracks global shark migration. Jekyll, a nine-foot-long juvenile great white shark weighing 400 pounds, swam by the Gaspé Peninsula, Que. on July 17. The longer and heavier Simon was detected south of Anticosti Island a day earlier.
Dany Zbinden, executive director of the gulf’s marine research station Mériscope, says it’s common for young, immature sharks to travel far from their natural habitats. It usually means their homes are oversaturated with predators and lacking in prey.
“That’s true for birds, mammals, and fish, but certainly great whites because they’re a travelling species that chase prey,” he says.
Great white sharks migrate to the Gulf of St. Lawrence every few years—Zbinden knows of Quebecois fishers from the 1960s who caught full-sized great white sharks in nets—because it’s a plentiful feeding region. But he says the rate of atypical travel observations for subarctic species, which includes great whites, has been increasing over the last few years due in part to warming temperatures along the coast.
“Marine species, on average, over the last 10 years along the Atlantic coast of Canada and the west, have moved upwards at an annual average of 20 to 25 kilometres. That’s not much in a year, but over 10 years…that changes an ecosystem,” he says.
Julien Poisson, director of southern Quebec conservation for the Nature Conservancy of Canada, says great whites rarely pose a threat to humans—sharks killed nine people in 2022 according to the International Shark Attack File. Instead, he says we should be concerned for the sharks. Lots of prey sites are degrading on the east coast of the U.S., so their presence in Quebec could mean they’re losing their native habitats.
“This isn’t a final conclusion because we don’t have the data, but usually when we see this type of occurrence it’s a bad sign,” Poisson says.