A homemade video showcasing a Tauranga man's encounters with local marine life, including patting eagle rays in knee-deep water, has taken on a life of its own online.

Nathan Pettigrew's video, Tauranga Moana is Awesome!, follows the keen kayaker's experiences on the harbour with orcas, octopuses, seals and bronze whaler sharks.

It's been a month since the clip, shot on his Go Pro camera, was posted on Facebook. As of 3pm yesterday, the video had 7145 shares, 2895 likes, and 117 comments.

Watch: Amazing life beneath Tauranga Harbour

Video courtesy Nathan Pettigrew

"To have 7000 shares and emails from around the world, places like Japan and China, is awesome but for me it was really just bringing awareness of what we have in the harbour and hopefully we can protect it," he told the Bay of Plenty Times Weekend.

Mr Pettigrew said he was stunned by the amount of interest and where the video had gone. "I'm surprised that a lot of people who live here don't know what's here," he said.

"I see people walking around the Mount and there are heaps of seals but they keep walking, they don't see there are orcas just out to their left.

"There's not many places in the world with as many things going on inside its harbour and it's all here."

Mr Pettigrew often invites interested people out on his paddles and said the motivation behind the video was "for people to say 'we've got all this, let's protect it'."

Mr Pettigrew is out on his kayak nearly every day and finds sharks on every trip.

"Within five minutes, they're there. If I only see one, that's a bad day." He's always been a big fan of sharks and "actually find them kind of calming in a weird kind of way".

"They just cruise. They have no interest in us at all." Mr Pettigrew's father would buy him books on sharks instead of toys when he was a child.

But it's the orcas he's fondest of and he's had countless experiences. "I was in 10 feet of crystal clear water when a mother and her calf came up alongside and just turned over and looked up at us. It was life-changing, just incredible."

Mr Pettigrew wants to video the blue whales that visit out past Motiti Island at this time of year.