A Vancouver Island fisherman is recovering in hospital after he was attacked by what a wildlife conservation officer said was an unusually aggressive black bear.

The attack occurred on Tuesday evening, moments after the fisherman boarded his boat.

The boat was tied up in a marina near Port Renfrew on the west coast of Vancouver Island.

Most likely the bear was drawn to the smell of salmon, swimming to the marina and climbed onto the deck of the boat.

Even after the 52-year-old fisherman tossed his salmon in the water, the bear continued to attack.

Vancouver Island conservation officer Gordon Hitchcock said it took several men to pry the black bear off the fisherman, who was later flown to a hospital in Victoria.

"This -- for Vancouver Island -- is not your typical black bear behaviour,'' Hitchcock told reporters.

When wildlife conservation officers arrived at the scene, they found the bear had died from injuries  sustained from knives and hammers, which the fisherman had used to subdue him.

Hitchcock said it is highly unusual for someone on Vancouver Island to be attacked by a bear while on a boat. "It appears to not have been in good health,'' said Hitchcock, who described the bear as an adult male.

The animal was undergoing a necropsy in Nanaimo Wednesday morning to determine what prompted the mauling. The fisherman was conscious when he was flown to Royal Jubilee hospital in Victoria.

But his name has not yet been released.