The farthest north the species has been reported until this year was off the coast of Oregon in 1997, said James A. Cosgrove, manager of natural history at the Royal British Columbia Museum. Before that year, the farthest north it was seen was near San Francisco, he said.

Until this summer, there have been no other sightings in the north, Cosgrove said.

"It's unprecedented," he said. "It speaks of a fundamental change in the ocean along the coast."