Since the time of the dinosaurs, sturgeon in the Columbia River had handled everything nature and man could throw at them.
But state biologists say the fish’s numbers have declined since California sea lions decided sturgeon is what’s for dinner, and the only fix they’ve found was telling the other top predator on the river dividing Washington and Oregon – humans – that they can’t have as many to eat.
The Oregon Fish and Wildlife Commission on Friday cut the total annual catch for sport and commercial fishermen in Oregon and Washington by 29 percent. Washington agreed to go along with the decision.
Once surveys determine that 17,000 fish have been caught and tagged, the fisheries in the Columbia and Willamette rivers will be shut down. And chances for a second season in the fall appear slim. The cut comes on top of a 40 percent reduction last year.
“We are concerned about recent declines in the sturgeon population,” Tony Nigro, department program manager, said in a statement. “Therefore, we’re being quite conservative in setting the harvest levels.”
White sturgeon are found in rivers from Alaska to Mexico, but the Columbia is the center of their universe, accounting for more of the fish than any other river. They can live to 100 and grow over 10 feet in length.
As recently as 10 years ago, their prime threats were drought, dams and people; the image of a sea lion breaking the water with a sturgeon in its mouth was one recalled only by veteran anglers or others who spend a lot of time on the water.
But now anyone going out on the Columbia from the mouth to Bonneville Dam is likely to see the drama of tooth and fin played out, especially in the prime spawning grounds below Bonneville Dam.
“That’s a real change in behavior on the part of sea lions,” said Oregon state fisheries biologist Tom Rien. “They have learned, or relearned perhaps, to hunt sturgeon.”
The problem is more than just sea lions, said Harry Barber, a volunteer for the Coastal Conservation Association.
State fisheries managers allowed too many fish to be harvested for years, and the fish that sturgeon eat are declining. Smelt and lamprey have both gone on the endangered species list in recent years, and shad are in decline.
Killing the sea lions is not an option; they are a protected species. But scaring them with fireworks and boats is allowed. And as a last resort, some are killed every year under a program to protect endangered salmon trying to get over the fish ladder on Bonneville Dam.
But the hazing hasn’t worked for sturgeon, which like to spawn in the fast water and clean gravel below the dam.
Washington biologists estimate sea lions could eat as many as 10,600 sturgeon this year on the Columbia. Oregon biologists figure they killed 7,000 over 5 years old last year.