Deep Sea Paradise Where Hammerhead Sharks Gather Around an Ancient Volcano

A deep sea paradise where hammerhead sharks gather around an ancient volcano has been captured on camera.

The footage is part of a Disney+ documentary, Epic Adventures with Bertie Gregory, which premieres on September 8. In the show, Gregory—National Geographic explorer, photographer and cinematographer—travels around the globe to capture wildlife phenomena on camera.

In this particular episode, Gregory sets off to the volcanic Cocos Island in Costa Rica in search of a shoal of scalloped hammerhead sharks.

Hammerhead sharks are an endangered species. They live in waters worldwide but their decreasing numbers mean it is often difficult to spot them in the wild. But this particular patch of ocean is different.

Gregory told Newsweek that it is one of the "last places on the planet where you still get big schools of hammerhead sharks."

Cocos Island is an oasis for wildlife. Its ecosystems are pristine, attracting an abundance of marine life, including elusive species such as the hammerhead shark.

"It's a totally magical place. Just imagine, just in the middle of the ocean, super deep, all of a sudden, there's this bright green, ancient volcano that erupts out of the water, and it's just covered in the most extraordinary jungle with waterfalls falling into the sea. It's a proper pirate's paradise," he said. "[Hammerheads] used to be very widespread. And unfortunately because of the shark fin trade, their populations have been decimated and this is really one of their last kind of strongholds. Filming them was a real challenge because of that. There aren't many of these big schools left."

In the footage, Gregory comes across a hammerhead with a fishing hook hanging out of its mouth.

Cocos Island is a national park, covering 1,989 square kilometers (770 square miles). This area is protected, meaning it is prohibited to fish here. But this hammerhead had clearly been swimming outside the protected areas, which is why it came into contact with fishing hooks, Gregory says in the footage.

"What makes it even more difficult [to get close to hammerheads] is that they're also surprisingly shy. I think when most people think of sharks they think of sort of, you know, a bold, confident predator. Whereas hammerhead sharks are proper scaredy cats. And so we have to use some cool technology to get close to them," Gregory told Newsweek.

The film crew spent a lot of time around the hammerhead "cleaning stations" to capture footage of the species.

"That is one of the best ways to find a hammerhead shark. They are a pelagic species, That means they love the open ocean. But when they come back to land they often do so to get cleaned. It's like a pampering spa session," Gregory said. "There's these little fish called barber fish that [will] swim into the reef and ... clean all their wounds and take parasites off when they're coming into the cleaning station. You just need to sit and hide in the rocks and wait. And they kind of go into this this crazy trance-like state when they are getting cleaned. It sort of looks like a dog getting a really good scratch."

Gregory said the film crew had "unexpected encounters" while filming.

One particular encounter saw a very large tiger shark interacting with the film crew in low visibility. Another saw the film crew sailing through the "infamous Drake Passage" in Antarctica, which is "one of the roughest areas of ocean on earth."

Epic Adventures with Bertie Gregory is set to premiere on Disney+ on September 8.