A massive shark was captured on camera swimming off the coast of Vancouver Island by a group of people fishing for tuna.

The group, which included former Vancouver Canucks hockey player Willie Mitchell, told CTV Vancouver Island they spotted a large shark fin while fishing near Tofino earlier this week.

“All of a sudden I just saw a big fin,” Mitchell said on Friday. “We lowered [a GoPro camera] down to have a look and the first thing we said was, ‘Oh my god, it’s a white. It’s a big white.’”

But after taking another look, Mitchell realized it was an almost three-metre-long salmon shark.

“They look so much alike,” he said. “You look at a salmon shark next to a white and they’re almost identical.”

Salmon sharks and great white sharks are both members of the same family. But unlike great white sharks, salmon sharks tend to shy away from mammals and focus mostly on chowing down on Pacific salmon.

“Pacific salmon sharks can be quite timid," explained Ruby Banwait, a senior biologist with the Vancouver Aquarium.

Despite their elusive behaviour, Mitchell said the shark sighting was still shocking, especially since he had gone for a swim earlier that day.

"What goes through my mind is when I jumped in the water and swam out there. There's lots lurking and you become pretty small in the world's oceans," he said. "You're in their domain so you've just got to respect it."

As many as 13 other species of sharks have been documented in B.C. waters, but catching a glimpse of one is rare, said Banwait.

Salmon sharks are most likely to be found further below the surface, even as far as 680 metres down.

But Banwait added the fact that this one was seen in B.C. waters is a good sign for the ecosystem.

"Seeing any shark is good sign. They're keeping the environment safe and healthy," she said. "They prey upon animals that are injured or sick, so things like that. They help to keep populations really healthy."

Experts have said that climate change could push sharks more commonly seen in southern waters to travel further north, including great whites.

The fearsome predators are usually found off the coasts of California and Australia but rising ocean temperatures could mean that more will move up to the northeast Pacific, a UBC researcher told CTV Vancouver in July.

With files from CTV Vancouver Island’s Jeff Lawrence and CTV Vancouver