Endurance swimmer Lewis Pugh is braving a great white shark hotspot on the 50th anniversary of the movie Jaws to highlight the importance of protecting the species.
Pugh, from Plymouth, Devon, began his 60-mile (96km) 12-day swim around Martha's Vineyard, an island off Massachusetts in the US, where the blockbuster was filmed, on Thursday.
It is the 55-year-old's latest feat after swimming the full length of the Hudson River in New York to raise awareness of water quality in 2023 and he also swam under Antarctic ice in 2020 to show the changes caused by climate change.
The activist said the challenge was "going to test my body and my mind".
Pugh said: "I'm a swimmer, I readily admit that I'm frightened of sharks – but I'm really frightened of a world without sharks, they're essential for a healthy ocean."
He said if an apex predator was removed from the land it would lead to a huge increase in other species.
That situation would lead to overgrazing and cause "ecological collapse", he said.
'Guardians of the oceans'
Pugh said the direct threat to sharks was overfishing.
"One hundred million sharks are killed every year, so on average that's 274,000 every day. It's ecocide," he said.
"But I think the greatest threat is indifference, it's the belief that sharks really don't matter, that this catastrophic crash in their numbers will not ultimately impact you.
"It will, because they're guardians of the oceans, and oceans are essential for all life on earth."
