Pacific Northwest waters seem to be teeming with exotic orcas recently as whale watchers and scientists report seeing record numbers of the distinctive mammals. Popularly known as “killer whales,” they have been sighted in clusters around the Strait of Juan de Fuca and Vancouver Island. The mysterious visitors usually congregate off the coast of California and are separate from the population of orcas known to call the Puget Sound home. Theories about what is attracting these marine mammals abound.
The subgroup of orca whales belong to a population group called transient orcas. These orcas prefer a diet of marine mammals, such as seals, making them distinctly different from the salmon-eating Puget Sound orcas. Whale watching professional, Mark Malleson of Prince of Whales Whale Watching, and research assistant with Fisheries and Oceans Canada reports spotting groups of the exotic orcas five times since September. That is a record in his 18 years in the whale watching business in the Pacific Northwest.
He has spotted the transient orcas near Port Angeles and along the Washington coast but not in Puget Sound itself, which remains the domain of the common orca natives. They spend a lot of time on the American side of the Strait of Juan de Fuca, probably because there’s an ample supply of their food source there, seals. It is rare to find them further east than Race Rocks, he explains. He suspects there are more out there than Pacific Northwesterners have seen. However, scientists are still observing and studying the exotic orcas in an attempt to understand their patterns of movement along the outer coast.
Malleson, who also volunteers at the Center for Whale Research on San Juan island, knows most of the regular orca population of the region by sight and notes that the newcomers are “fatter and sassier” than the Pacific Northwest natives. The are also more leery of boats and take longer dives. Furthermore, they run silent just before striking at their prey. He witnessed a coordinated attack by three orcas on one seal last fall, which they proceeded to divvy up and share. They are not competing with the resident killer whales for food nor for breeding so they pose no threat. The scientist whale watcher recognized a solitary male near Port Angeles who used to travel in a pair with another orca. The two were presumed to be brothers but the second orca has not appeared for a few years so scientists assume he is dead.
Northwest Fisheries Science Center wildlife biologist, Brad Hanson, says that scientists are perplexed as to what is luring the exotic orcas to the Pacific Northwest in record numbers than in recent memory. One explanation is a population increase among the species. But an increase in the population of their prey,the sea lions and seals could also be an important factor in explaining why it is more common to see them this year. Another mystery is why the Sound’s resident orca population is declining while the exotic population off the Pacific Northwest coast is healthy and flourishing.
by Tamara Christine Van Hooser
Image courtesy of Ingrid Taylar – Flickr License