The largest tagged male great white shark in the Atlantic Ocean has been identified traveling up the US and Canada coastline amid a surge in sightings of sharks that are increasingly shifting their movement patterns due to the overheating of the oceans.

The great white shark, named Contender, is nearly 14ft long and weighs more than 1,650lbs. The hulking fish has been pinged in several locations off North Carolina and Maine as he headed north for the summer, with Contender’s last known location located off Nova Scotia in Canada on 11 July.

Contender is the largest male ever tagged in the Atlantic by Ocearch, a shark research organization, which first attached a satellite tag to his dorsal fin in January last year. The giant predator, thought to be 30 years old, shuttles between Florida and Canada in his seasonal migrations. Ocearch said it is confident that Contender, named after a research boat, is now summering in Canada.

The identification of Contender’s movements comes as shark sightings have surged in locations including New York and California. There have been 16 sightings of sharks just in July off Rockaway Beach in New York City, a situation that has spurred some nervousness. “It’s a little scary,” one beachgoer told NBC.

But scientists point out that while the chances of being attacked by a shark remains very small, rising ocean temperatures, caused by the human-driven climate crisis, are altering the range of several shark species, sometimes bringing them closer to where people are swimming or surfing.

“We are seeing evidence of a northward movement because of the warming waters and that means for there’s more chances to see sharks,” said Shannon Barry, a researcher at the Florida Institute of Technology who led recent research finding that bull sharks have moved up the US’s east coast.

“Bull sharks are definitely going to be more near shore – they can go into low-salinity environments such as estuaries and near rivers, so that is something to keep in mind,” she said. “There is a potential increase in human-shark interactions as they are moving into places where people go to swim and fish.”

This prospect does concern some people, Barry acknowledged, but she added that it was more striking that the morphing composition of the oceans was causing such a change.

The global water surface temperature hit a new record high last month, the latest in the string of remarkable recent heat records as the ocean, which soaks up 90% of the excess heat caused by the burning of fossil fuels, rapidly warms up and acidifies. A developing El Niño, a periodic climatic event, is also driving up ocean temperatures.

Most sharks do not like the cold and so are able to venture northwards as the oceans warm up and prey species distribution changes, although the extra heat may soon become so extreme that great white sharks face the risk of fatally overheating, researchers recently warned.

“The reaction should be concerning because we can see sharks are the canary in the coalmine to this problem,” Barry said. “Bull sharks generally hang out in south Florida and the Bahamas and now we are seeing them moving. That is something that people can see and think, ‘Oh, I can see the effect of climate change there.’”

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This month, a man visiting a beach in Florida said he was bitten on the foot by a shark, causing the release of a “whole lot of blood” as he attempted to get his pregnant fiancee to safety. But there is little evidence of an increase in such incidents and attacks on people remain rare, with only 65 unprovoked shark bites on humans recorded worldwide in all of last year, with 25 of these in the US.

By contrast, humans kill about 100 million sharks a year by accidentally tangling them in fishing nets or actively catching them for sport, food or the shark fin trade. Removing sharks can damage whole marine ecosystems, Barry said. “Seeing a lot of sharks is usually a good thing; it means the surrounding food web is healthy,” she said.

Conservation measures and increased surveillance means that some shark numbers are recovering and they are being spotted more easily, according to Neil Hammerschlag, executive director of the Shark Research Foundation, but global heating is pushing them into places where they haven’t been seen before.

“We are seeing tiger sharks, for example, moving north of Cape Cod, and previously that would be very, very rare,” he said. “Still, fear of sharks shouldn’t deter anyone from enjoying the ocean. Sharks generally don’t want to be around people; they try to avoid us. We are like aliens to them.”

Hammerschlag added, though, that humans are “just visitors to the ocean and we should be shark aware”. This includes avoiding wearing shiny jewellery in the water, which can resemble the scales of a fish, or swimming at dusk or when there’s an unusual amount of fish activity.

“We have to be aware we are not the only ones in the ocean,” he said. “Sharks aren’t lurking in the water, they are living in the water. We are in their territory.”