Divers working around sea cages in Passamaquoddy Bay do not need to take additional precautions after a shark attack last month, according to a shark expert.

A diving crew was conducting an environmental assessment on a former salmon cage site just off the coast of Maine, near Deer Island, N.B., when a porbeagle shark attacked a diver.

Chris Heinig was assisting diver Scott MacNichol, who surfaced immediately and jumped into the small boat. He estimates the shark was about 134 kilograms and 2.4 metres long.

A brief video shows the head of the porbeagle shark, with its jagged teeth clearly visible, as it smashes into the diver's camera.

"He had a tail of a large fish draped over his shoulder," Heinig said.

Heinig contacted the U.S. National Marine Fisheries Service and those experts said they believed the shark thought the diver's video camera was food.

"The camera housing that we use is silver, it's shining, it has a camera in it with a battery," Heinig said.

Heinig said from a shark's perspective, the camera could look like a fish or small school of fish.

MacNichol was not injured in the attack.

Shy, elusive sharks

Steve Turnbull, a shark expert at the University of New Brunswick, said he agrees the shark likely mistook the camera for some food in the cold waters of the Bay of Fundy.

Turnbull has a lot of underwater experience with sharks and has reviewed the video of the attack on MacNichol.

He said porbeagles, which look like small great white sharks, are shy, elusive and eat fish, not mammals.

"There's been no bites, no fatalities or anything attributed to porbeagles. They are primarily eating fish. That's pretty much it," Turnbull said.

Turnbull said he has had his camera attacked on more than one occasion, though not in the Bay of Fundy.

Scientists confirmed a new breeding ground for porbeagle sharks on Georges Bank in 2008.

The porbeagle population reached dangerously low levels in the mid-1990s.

It's estimated there are about 190,000 porbeagles in Canadian waters — putting the stock at about one-quarter of its level in 1961.