VINEYARD HAVEN, Mass. (AP) — Lewis Pugh has followed an unspoken rule during his career as one of the world’s most daring endurance swimmers: Don’t talk about sharks. But he plans to break that this week on a swim around Martha’s Vineyard, where ” Jaws” was filmed 50 years ago.

The British-South African was the first person to complete a long-distance swim in every ocean of the world — and has taken on extreme conditions everywhere from Mount Everest to the Arctic.

“On this swim, it’s very different: We’re just talking about sharks all the time,” joked Pugh, who will, as usual, wear no wetsuit for the 62-mile swim.

For his swim around Martha’s Vineyard in 47-degree water he will wear just trunks, a cap and goggles.

Pugh, 55, is undertaking the challenge because he wants to change public perception around the now at-risk animals — which he said were maligned by the blockbuster film as “villains, as cold-blooded killers.” He will urge for more protection for sharks.

“We need to protect life in our oceans — all our futures rely on it,” he said on Thursday before starting out from a beach in front of the Edgartown Harbor Lighthouse and swimming an initial 3.9 miles for nearly three hours. Today, he’ll get in the water and swim again — and again, for an estimated 12 days, or however long it takes him to complete the swim. He’ll spend the rest of his time on the Vineyard educating the public about sharks.

Later Thursday, he crawled out of the water, where curious seals bobbed in the waves, and onto a boat to warm up and refuel.

He began his endeavor just after the New England Aquarium confirmed the first white shark sighting of the season, earlier this week off the coast of Nantucket.

“It’s going to test me not only physically, but also mentally,” he said, while scoping out wind conditions by the starting line earlier this week. “I mean every single day I’m going to be speaking about sharks, sharks, sharks, sharks. Then, ultimately, I’ve got to get in the water afterwards and do the swim. I suppose you can imagine what I’ll be thinking about.”

Pugh said the swim will be among the most difficult he’s undertaken, which says a lot for someone who has swum near glaciers and volcanoes, and among hippos, crocodiles and polar bears. No one has ever swum around the island of Martha’s Vineyard before.

But Pugh, who often swims to raise awareness for environmental causes — and has been named the United Nations Patron of the Oceans for several years — said no swim is without risk and that drastic measures are needed to get his message across: Around 274,000 sharks are killed globally each day — a rate of 100 million every year, according to the American Association for the Advancement of Science.

“It was a film about sharks attacking humans and for 50 years, we have been attacking sharks,” he said of “Jaws.” “It’s completely unsustainable. It’s madness. We need to respect them.”

He emphasizes that the swim is not something nonprofessionals should attempt. He’s accompanied by safety personnel in a boat and kayak and uses a “Shark Shield” device that deters sharks using an electric field without harming them.

Pugh remembers feeling fear as a 16-year-old watching “Jaws” for the first time. Over decades of study and research, awe and respect have replaced his fear, as he realized the role they play in maintaining Earth’s increasingly fragile ecosystems.

“I’m more terrified of a world without sharks, or without predators,” he said.