A lone grey whale with very bad directions has ended up in the murky Fraser River instead of the picturesque Baja peninsula.

First reported by a tugboat operator Monday morning near the Port Mann Bridge, and seen again yesterday off the New Westminster Quay, the grey whale is 20 miles upriver - and a long way from home.

Pacific grey whales usually pass through B.C.'s coastal waters on their way to the Mexican Baja peninsula in November and start heading north again in February.

The whale's appearance here in January, never mind in a fresh water river, has left local marine biologists baffled.

According to B.C. Cetacean Sightings Network co-ordinator Bethany Lindsay, whales of any species are "almost never" seen in this part of the Fraser.

"It could have just gotten lost, it may be sick or injured, or it could have been scared into there by killer whales or loud boats," she mused.

But while it may be exciting to catch a glimpse of the rogue whale wandering this close to the shoreline, a grey whale inhabiting a freshwater river way can be dangerous, warned Lindsay.

The whale won't be able to find it's regular diet of small, shrimp-like animals that live only in the ocean bed, and fresh water can cause significant damage to the whale's skin, she said.

If the loner can't find it's own way back to the ocean by next week, "there may be an operation to chase it out of the river."