Likely lost and alone after taking a wrong turn, a wayward grey whale has been sighted swimming up the Fraser River, at a time when most of its compadres are migrating south for the mating season.

Whale watchers have reportedly dubbed the mammal, dotted with its characteristic grey-white marks, "Moby."

It was first spotted Monday by a tugboat operator near the Port Mann Bridge.

But Dr. Lance Barrett-Lennard cautioned that although the animal may not be under threat of being hunted anytime soon, prolonged exposure to the river water could be a danger.

Barrett-Lennard, a whale expert heading the Vancouver Aquarium's Whale Research Program, explained that a grey whale can stay in fresh water for two or three weeks, but eventually the water could harm its skin and it could suffer.

He has also warned curious whale watchers to keep their distance, since spooking the whale could drive it toward shallow water, where it could become beached.