Sea Lions Show Salmon
by John Ritter, staff writer
BONNEVILLE, Ore. -- In the swirling spillway of this massive hydroelectric complex on the Columbia River, a wildlife worker in a small boat trains his rifle on a California sea lion.
Whether his rubber bullet hits the 500-pound pinniped and scares it away from a juicy buffet of chinook salmon can't be readily determined. Biologists are skeptical.
"Some of them barely feel it," says Robert Stansell, a fisheries biologist with the Army Corps of Engineers. "When you hit them point-blank, they'll just turn around and look like a mosquito bit them."
Hazers, as the shooters are called, from the corps and wildlife agencies in Oregon and Washington state also fire shells that explode charges equal to M-80s in the air and underwater. They have tried mimicking the sounds of killer whales, which eat sea lions, to frighten them off. If they can get a sea lion's attention, hazers try to chase it back downstream.
In greater numbers every year, sea lions swim more than 100 miles up the Columbia from its mouth at the Pacific Ocean to Bonneville as endangered salmon congregate in April and May on their way upriver to spawn. Last year, biologists identified at least 80 sea lions at the dam.
"They've definitely been coming earlier every year, leaving later, staying longer," Stansell says.
It's a rare instance of one protected species, sea lions under the Marine Mammal Protection Act, preying on another protected species, chinook salmon listed under the Endangered Species Act.
Chinook salmon are the losers. Their numbers have been declining for years because of commercial and sport fishing, loss of habitat and the difficulty of negotiating dams on the Columbia and its tributaries. About 100,000 salmon a year now swim up Bonneville's fish ladders, structures designed to help fish get around the dam.
Sea lions, reduced to about 50,000 when Congress passed the protection act in 1972, have flourished: More than 300,000 now roam the Pacific coast.
Last year, biologists estimated that the wily pinnipeds took an estimated 3% to 4% of the Columbia's chinook run. Sea lions return to the ocean in late May to head for breeding grounds in Southern California.
"Everybody is doing a lot of things to try to allow these fish to recover," says Robin Brown, a marine mammal researcher with the Oregon Fish and Wildlife Department. "But all of a sudden, we have a whole new source of mortality that shows no sign of stopping."
From 500 to 1,000 sea lions prowl Columbia waters between the dam and the ocean, Brown says. They catch an unknown number of salmon.
This year, the department installed a floating barge near the dam to lure sea lions to rest -- or "haul out" -- on it. When they do, a net drops and traps them for transport downriver to Astoria, on the coast, where thousands of pinnipeds haul out.
Last month, Washington, Oregon and Idaho -- the Snake River is part of the Columbia system -- asked the National Oceanic and Atmospheric Administration for permission to kill some of the sea lions. That kicked off a lengthy public process that will require "a year or more" to reach a decision, agency spokesman Brian Gorman says.
In the late 1990s, Washington state made a similar request when a few sea lions, gorging on steelhead trout at Ballard Locks at Seattle's Lake Washington, slashed the spring run from 500 fish to 70 over a few seasons. Those animals were spared when SeaWorld in Orlando agreed to take them.
Members of Congress from Washington and Oregon are sponsoring a bill to amend the protection act to allow the killing of problem sea lions, but it's not likely to pass in time to stop this year's banquet, says Rep. Brian Baird, D-Wash. "Sea lions are smart enough to realize if it becomes a lethal risk, they're going to have to go somewhere else or change their strategy," Baird says.
The Oregon Humane Society won't oppose killing Bonneville sea lions if the states show that other measures have failed, Executive Director Sharon Harmon says. "I recognize the political reality," she says. "We could end up with no salmon while we discuss the issue to death."
Four Indian tribes on the lower Columbia that have strong cultural connections to chinook salmon are "outraged" that sea lions are eating their sacred fish, says Charles Hudson, spokesman for the Columbia River Inter-Tribal Fish Commission. Salmon are "highly prized for ceremonial functions, including funerals, weddings and other celebrations," he says.
Salmon usually can evade sea lions in the open ocean, Brown says. Once in the river, the fish tend to hug the shoreline and are somewhat more vulnerable, but as they mill around below the bottleneck of a dam, sometimes for days or weeks before entering a fish ladder, they're a virtual sushi bar for sea lions. Even a 30-pound salmon is no match for a sea lion.
One particularly aggressive sea lion, dubbed C404, became something of a celebrity last year. Nothing hazers tried persuaded him -- practically all marauding sea lions here are males -- to leave. C404 pioneered a tricky jump maneuver that got him inside a fish ladder, where the pickings were easy.
That prompted officials to install heavy bars in front of most of the gates leading to ladders. Even so, C404 was spotted this year early in the salmon run, trying to figure out how to get back inside.
When a handful of sea lions first came to Bonneville about five years ago, they'd eat salmon for a while, then go back downriver to Astoria.
As more sea lions went upriver each year and as they became more comfortable around the dam, they began hauling out on nearby shores and concrete structures instead of returning to the coast.
Data from last year, when sea lions were harassed only intermittently, indicate that more salmon were eaten during hazing than when the animals were left alone, Stansell says. He thinks that could be because when the sea lions are resting, they're not chasing salmon.
This year, hazers in boats, helped by spotters on the riverbanks and atop the walls of the dam's power stations and spillway, will patrol daily from dawn to dusk.
Sea lions are smart and adaptive, and with stepped-up hazing their behavior has changed. "They stay underwater a lot longer," Stansell says. "They're not showing themselves as much.
"The ones that already know there's a feast here, they're tough to drive off."
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