The Feeding Frenzy That Got Sea Lions Into Deep Trouble – The Atlantic

Let us first establish that sea lions are supposed to live in the sea.

Since the 1990s, however, male sea lions—a handful at first, now dozens—have been captivated by the attractions of the Willamette River. They travel all the way from Southern California to Oregon and then swim up 100 miles of river to arrive at an expansive waterfall, the largest in the region. Here, salmon returning to spawn have to make an exhausting journey up the fish ladders of the Willamette Falls. And here, the sea lions have found a veritable feast.

“They’re kind of sitting ducks,” the wildlife biologist Sheanna Steingass told me, describing the salmon. She paused to consider the metaphor. “Or sitting fish.” Every sea lion eats three to five fish a day.

In another world, this could just be a story about the intelligence of sea lions and their adaptability to river life. But in this world—where salmon populations throughout North America have plummeted, and where the winter steelhead run at Willamette Falls has fallen from 25,000 fish in the 1970s to just hundreds in 2018—it’s a dire story for the fish. After spending years trying and failing to deter the sea lions by nonlethal means, the Oregon Department of Fish and Wildlife, where Steingass leads the marine-mammal program, started “lethal removal” of sea lions in December. As of mid-January, they have trapped and euthanized five sea lions at Willamette Falls.

Killing animals to save other animals is always controversial. Animal-rights groups like the Humane Society of the United States denounced the sea-lion killings, calling them a distraction from the salmon’s real problems. And it’s true that a long chain of human actions—overfishing, destruction of salmon habitats, dams blocking their migration, hatchery mistakes—have led to what everyone can admit is this nonoptimal situation.

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“In a perfect world, in an unaltered world, this wasn’t a problem, because historically there were 16 million salmon in the Columbia River,” says Doug Hatch, a senior fisheries scientist at the Columbia River Inter-Tribal Fish Commission. The sea lion’s appetites would have barely made a dent. It’s only because humans have so unbalanced the natural world that as drastic an action as culling sea lions could appear to be the fix.