A nearly 4.2-meter-long great white shark named Contender made headlines after traveling north from Florida to the chilly waters off Nova Scotia, an eastern Canadian province. He was not alone. More great whites have been spotted along Canada’s Atlantic coast in recent years, raising questions about what is drawing them north and whether people should be concerned.

While no single factor fully explains the trend, the St. Lawrence Shark Observatory says the gradual recovery of Northwest Atlantic shark populations following decades of legal protection in Canada and the United States may be a major driver. Another major factor is the increase in marine mammals, which in turn increased food availability for the great whites.

Seal populations have grown along both countries’ coasts, providing abundant prey. Warming ocean temperatures may also be pushing fish populations northward, supplying more food for seals and, indirectly, the sharks that hunt them.

On the other hand, some scientists believe the increase in sightings may reflect changing shark movements rather than population growth. Marine biologist Neil Hammerschlag and his team identified 120 individual great whites over 55 days last year. About 80% were seen only once, suggesting that many were passing through rather than remaining in the area. More people boating and diving along the coast may also explain the rise in reports.

The increased shark presence has raised some safety concerns. In September, a great white attacked a diver off Quebec’s Gaspe Coast, causing non-life-threatening injuries. While people should remain cautious, experts say sharks rarely target humans.

Fewer sharks are expected between October and March as temperatures drop, but many may return next year. As sightings increase, Canadians are learning to share the coast safely with their seasonal visitors. As dive instructor Alanna Canaran says, “It’s about relearning how to live with them. We’ve done it before, and so I’m confident that we can do it again.”