Sea Lion Shuttle Service Not A Substitute For Lethal Removal At Willamette Falls
Threatened winter steelhead will start making their way up the Willamette River to their spawning grounds next month, and half a dozen sea lions are already waiting to eat them at Willamette Falls.
Managers with the Oregon Department of Fish and Wildlife have asked for permission to kill these sea lions to save the fish. They don’t have an answer yet, but thanks to a sea lion shuffle earlier this year, they’re ready to go should they get the approval.
Last year, sea lions at Willamette Falls ate a quarter of a winter steelhead run that was already down to about 500 fish. At that rate, biologists say, the run is at risk of extinction.
Oregon has permission to kill sea lions to protect fish at Bonneville Dam, where 29 sea lions were lethally removed last year. But they don't have that option at Willamette Falls, about 10 miles south of Portland where the river divides Oregon City from West Linn.
Without authority to kill the sea lions at Willamette Falls, fishery managers got creative.
The state trapped and relocated about a dozen sea lions in two cages on a dock below Willamette Falls between February and April.
In many of those cases, Bryan Wright, who leads ODFW's marine mammal program, would hide out of sight at dusk until he saw a sea lion jump into the trap. Then, he'd press a button and a heavy cage door would slam shut.
Once the sea lions were trapped, Wright and other wildlife managers shooed them from the dock to a barge to a pickup truck – and then drove them 200 miles away to Newport.
“So, now we’re transferring the animal from the barge to the truck," Wright explained from behind the wheel of a pickup truck as a team of workers banged on the walls of the barge with poles. “Usually you have to use a little bit of noise, tapping the stick, prodding them a little bit.”
The sea lions weren’t exactly eager to hop into a cage on the back of a truck, and Wright wasn’t exactly thrilled to be behind the wheel.
“It’s not something anybody does every day," he said. "You have this 400- to 600-pound sea lion in the back, and nobody really knows, you know, driving by what we have back there. The first time I did it I was a bit white knuckled for the whole trip.”
Sea lions swim right back
Even as he was releasing these sea lions, Wright knew it was just a matter of time before they swam right back.
One sea lion made the 230-mile trip in just four days. Another one swam back and got trapped a second time, so he got two trips to the coast.
Shaun Clements, a fisheries manager with ODFW, said clearly driving the sea lions to the coast was not a solution to the problem. But it is one of their only options for protecting the fish while they wait for approval to kill the sea lions.
“In the meantime, we felt we had to do something because the run is so poor and the sea lion population is getting bigger,” he said.
For every day the relocated sea lions weren’t at Willamette Falls, the agency estimates it saved two to three fish from getting eaten. Multiply that by 10 for each of the sea lions they moved, Clements said, and the number of fish that weren't eaten by sea lions starts to add up.
"We did save some steelhead from predation," Clements said. "Sixty days of two fish each a day, that’s 120 fish. That’s something"
Plus, he said, now they have the traps and the barge system ready to go to lethally remove sea lions should they get permission from the National Oceanic and Atmospheric Administration.
Trucking sea lions and salmon
But killing sea lions won’t solve all the problems these fish are facing.
The salmon and steelhead that do make it over the falls – without getting eaten by sea lions – still have twelve dams standing in the way of their spawning grounds.
None of those dams have fish ladders — a stair step-like series of pools that allows fish to make their way up and around a river's towering dam.
“So right now what you see in essence is a huge roadblock for these fish in both directions,” said Jennifer Fairbrother with the Native Fish Society, an environmental group that sued the U.S. Army Corps of Engineers over dam management in the Willamette River Basin. “The big nut to crack is how do we help these fish get around the dams both as they go downstream as juveniles and as they come back to spawn?”
Right now, dam managers have to help adult fish get around the dams by collecting them in a holding tank that drains into a truck. The truck drives the fish around the dam and dumps them out upstream.
Sea lions aren’t the only wildlife getting trucked around Oregon. More than half the salmon in the Willamette River Basin – tens of thousands of fish – get driven around dams every year. It’s the only way they’ll make it.
The dams were built for flood control, and dam managers says they’re too tall for regular fish ladders and spillways.
"In a perfect world, we’d have a ladder where we didn’t have to trap and handle fish," said Greg Taylor, fisheries biologist with the U.S. Army Corps of Engineers. "Everybody wants that. But it’s not a tool that’s available to us at this point. It’s not there.”
While dam managers puzzle over better options, sea lions are eating more and more of the fish downstream.
Clements says the only option left is to kill the sea lions to save the fish – before it’s too late.
“It’s a pretty simple equation for the winter steelhead right now," he said. "Their numbers are so low. They’re losing so many here at the falls, that if we don’t do this they’re going to go extinct.”
ODFW is expecting a decision on its application to lethally remove sea lions from Willamette Falls by the end the year.
Copyright 2020 EarthFix. To see more, visit .