There are two distinct populations of killer whales in the Salish Sea. The most famous are the so-called Southern Resident killer whales, an endangered clan currently down to 73 members. But there’s an entirely different orca ecotype—who have not had any kind of genetic interaction, according to scientists, for at least 300,000 years and perhaps longer, with the SRKWs—who are known as “transient” orcas, scientifically known as “Bigg’s” whales.

While the resident orcas are strictly very picky fish eaters—some 80% of their diet is Chinook salmon—Bigg’s are mammal eaters. They eat seals, porpoises, sea lions, and sometimes humpback and grey whale calves. They are rapacious hunters. I’ve observed them peacefully playing and traveling together and then suddenly go on the hunt, and it’s terrifying. They are incredibly fast, nimble, and immense all at once. 

I happened to get video of them hunting seals near Grandma’s Cove on San Juan Island’s southern coast this summer. I couldn’t say for certain whether they were successful, but they seemed to be, since they appeared to linger just under the surface near this spot for quite a while afterward, as if they were feeding.

For what it’s worth, the Bigg’s orcas are anything but endangered. Their population appears to be healthy and growing. We’re also seeing them a great deal more in the interior waters of the Salish Sea than we used to, in part because we’re seeing residents—who notoriously chase the Bigg’s orcas, who travel in smaller pods, out of their waters—so infrequently.

The other big piece of that puzzle is the great abundance of pinnipeds in the area now, whose population is flourishing along with a bountiful supply of baitfish. That’s drawn more Bigg’s orcas, naturally. There’s a reason that local wags sometimes refer to the harbor seals sunning themselves on haulouts as “rock sausages,” and not just because that’s what they look like. 

The wise scientists I talk with about all this tell me that these are all signs that the oceanic ecosystem here is changing, away from the larger fish like salmon that used to dominate and toward the smaller baitfish that nourish seals and attract humpback whales too. I believe them.