Washington State's Fish and Wildlife Department is warning people along the coast that a great white shark is swimming in its waters after a dead half eaten seal was found on the beach. 

A harbour seal that washed up on the beach in the tourist town of Ocean Shores this week had been partially devoured by the predator, providing evidence of the rare shark which is not often seen in this area.

Christopher Lowe, a professor of marine biology at the California State University Long Beach and the director of the school's Shark Lab, says sightings of great white sharks north of California are unusual, but not unheard of.

"White sharks, compared to other species of sharks, can actually go into colder water," said Lowe. "They can keep their bodies warmer than the water."

Lowe says great white sightings may become more common off the coast of B.C. because of warmer ocean temperatures allowing them to move further north.

He says more sightings could come as a result of decades of legislation and environmental management that are enabling the whole food chain to flourish.

"It's good sign to see big predators," said Lowe. "It means your ecosystem is coming back."

Lowe says the same conditions could also lead to an increase in dolphins, seals and whales. But he doesn't think the changes would lead to a permanent great white shark population off the B.C. coast.

"My guess is as long as your orcas are there, you won't have to worry about too many white sharks visiting, at least not spending a lot of time," said Lowe.

Other than humans, orcas are the only creature that could threaten a great white shark.

Lowe says that great white shark attacks are extremely rare and are more likely found in areas with big seal populations.

To listen to the full interview, click on the audio labelled: Great white shark lurking of Washington coast