Record numbers of "exotic" orcas have mysteriously been frequenting waters in the Pacific Northwest, typically unchartered territory, and researchers are trying to figure out why.
Transient killer whales are comprised of two populations - an estimated 304 individuals inhabiting the inner coast and another 217 on the outer coast, according to The Vancouver Sun. The outer-coastal cousins, or "exotic" orcas, commonly swim off the edge of California and as far north as Alaska.
But since September, The Seattle Times reports, these whales have abandoned the Puget Sound where they feed on salmon and made their way to the inland waters of Washington and British Columbia instead.
Mark Malleson of the Victoria-based Prince of Whales Whale Watching says he has spotted the outer-coastal orcas five times - more than he's ever in his 18 years in the business.
"Frankly, we don't know a lot about the movement of these whales on the outer coast," Brad Hanson, a wildlife biologist for the Northwest Fisheries Science Center, told The Times.
Experts don't know for sure what's driving their unique movements, but they suspect that a boom in seal and sea lion populations may be attracting these whales in unprecedented numbers.
Given that outer-coastal orcas eat everything from Dall's porpoises to northern fur seals and northern elephant seals, it's likely they would not want to miss a feast like this.
"Harbor seals were very scarce," expert John Ford told The Sun. "There are now 10 times more harbor seals in the Strait of Georgia. It's definitely on their [whales'] radar."
Harbor seals, hunted for their pelts, were once low in numbers, but when a law passed in the 1970s prohibited killing them without a permit, they bounced back. Seal populations are at their highest usually in August and September when pups are born, luring in any hungry predators nearby.
But while the exotic orcas seem to be fat and happy, the Puget Sound population of resident orcas is suffering. There are only 78 left in the area, the lowest it's been in the last 30 years, and their numbers still continue to drop.
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