Chad Patti, 30, and his pal were spearfishing some 70 miles off the coast of Florida when he was attacked by a 10ft mako shark.
Terrifying footage showed the moment Patti was mauled by the beast on New Year’s Day.
He was using a GoPro attached to his head to record himself spearfishing with his friend Josh Loucks in the waters off Pensacola.
And as he came to the surface after a dive, he captured the moment a massive mako shark suddenly appeared below the surface and charged at him.
The terrified fisherman could be heard screaming for help as his friend leapt into the water to help him.
The beast chomped down on his fin before vanishing – and Patti said he was convinced he had lost his leg.
He told Pensacola News Journal: “It basically shoved my knee to my chest, almost knocked the wind out of me, knocked my gun out of my hand, partially flooded my mask and I did a summersault in the water.
“The first scream, the ‘help,’ I didn’t think I had a leg, honestly.”
“It wasn’t just a bump. I got it [the video] slowed down five times the speed and you can see the shark clearly has the fin in its mouth. You can see him crush it.
“It was a predatory strike from the mako. I was his prey. There was no mistaken identity. There was no fish in the water. No blood in the water.”
Patti was miraculously uninjured in the attack.
He said the shark grabbed his fin as it launched itself at him – a popular hunting tactic used by the species to immobilise their prey.
“It did what any mako does. It kind of takes out the motor, cuts the tail off the fish in the first strike and then it doubles back and finishes it off,” Patti said.
“When it hit my fin, what it was doing was it was trying to take the motor out.
“Luckily the boat was there and my buddy Josh jumped in the water.”
Patti said he “never saw a sign of a shark except the fish being a little spooked”.
Despite the terrifying ordeal, he said it won’t stop him from heading back out into the ocean.
“I’m not going to let it stop me from doing something I love,” he said.
According to Oceana, mako sharks can swim up to 45mph.
And although they are known for being aggressive, attacks on humans are rare.
According to the International Shark Attack File, nine attacks on humans have been recorded between 1580 and 2022. Of those nine, three were fatal.