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Biologists Tell Council That Sea Lion Predation Puts Willamette Winter Steelhead At Extinction Risk
Posted on Friday, September 22, 2017 (PST)

As the steelhead population above Willamette Falls declines, sea lion predation increases, putting the endangered fish at risk of extinction with only 512 making their way upriver.


Until 1998, Willamette winter steelhead numbers above the falls bounced up and down from 5,000 to more than 20,000 a year. For 20 years they have been mostly on a downward trend with population spikes in 2002 and 2003 of 15,000 and 10,000 respectively. This year the count has biologists worried.


A presentation at the Northwest Power and Conservation Council’s September meeting in Spokane gave Willamette winter steelhead an 89 percent chance of going extinct.


Biologists are struggling to make non-lethal deterrents solve the problem, but others are asking Congress to help by changing restrictions in the Marine Mammal Protection Act.


Dr. Shaun Clements, research scientist and native fish investigations program leader for Oregon Department of Fish and Wildlife and Steve Jeffries, research scientist for Washington Department of Fish and Wildlife, presented their argument for lethal take of California sea lions to the Council’s fish and wildlife committee Sept. 12.


In their presentation Clements and Jeffries said Willamette winter steelhead, already in low abundance due to a variety of factors, have seen predation of adult fish attempting to pass the fish ladder at Willamette Falls by sea lions this year in the 20-25 percent. To protect the steelhead Oregon has applied for a lethal take permit in an effort to protect the remnants of a once-productive run.


Oregon Fish and Wildlife biologists have monitored sea lion predation on salmonids, sturgeon and lamprey at Willamette Falls for the past four years. As noted on the department’s website, monitoring efforts started in January 2017 trapping sea lions at SportCraft Landing Moorages in Oregon City in order to brand unmarked individuals and to potentially relocate sea lions back to the ocean.


Clements said for the most part non-lethal hazing doesn’t work. The only effective non-lethal method was blocking fish ways to prevent sea lions from feeding on steelhead.


“Nonlethal is not going to move them out of the area, just around the fish way entrances,” Clements said.


Clements said the largest abundance of sea lions in the basin is between December and March.

California sea lions in the Columbia Basin are most abundant in Astoria, totaling about 3,000.


Between 100 and 1,000 have been observed at the Bonneville Dam, 10 to 15 have been found in the Clackamas River and a couple made their way into the Sandy River this year. While only 10 to 100 have been seen at Willamette Falls, their impact has been startling. Sea lions are also making their way into the Cowlitz, Kalama and Lewis Rivers in Washington.


“It’s a worrisome trend,” Clements said.


To lethally remove sea lion the rules say one has to be seen for five days and/or be seen eating salmon or steelhead. Hazing efforts are not producing the desired results.


Clements said, “We know they are there eating salmon, but it’s harder to determine the individuals eating salmon and that opens us up to litigation. Eight out of 10 animals didn’t meet the criteria. We need to change the criteria so we could remove 10 out of 10.”


Currently there are bills in both the House and the Senate that would make it easier to lethally remove sea lions under the Marine Mammal Act.


Clements said, “No doubt the bill will make its way out of the House, but we need a Democrat sponsor in the Senate. One Northwest senator could give it enough gas to be heard in committee and move it forward into the full Senate.”


Meanwhile, the Council on Sept. 14 sent a letter to Congress supporting “the Endangered Salmon and Fisheries Predation Prevention Act.”


“The Northwest Power and Conservation Council strongly supports S.1702, the Endangered Salmon and Fisheries Predation Prevention Act. After witnessing the alarming increase in sea lion predation on salmon, steelhead, sturgeon, and lamprey in the Columbia and Willamette rivers in recent years, we believe that it is incumbent upon Congress to provide the Northwest’s state and tribal fish and wildlife agencies more effective options for protecting our fish and fisheries from these aggressive predators. Failure to do so risks the extinction of some of our most precious and important fish species, including at-risk populations of spring Chinook salmon.”


The full text of the letter can be found at


Also see:


-- CBB, Aug. 11, 2017, “ODFW Analysis: With Continued Sea Lion Predation Willamette Winter Steelhead At Risk Of Extinction”


--CBB, June 23, 2017, “Oregon To Seek Permit To Lethally Remove Salmonid-Eating Sea Lions At Willamette Falls,”


-- CBB, March 10, 2017, “Corps Report: Sea Lions In Bonneville Dam Tailrace In 2016 Consumed 4.5 Percent Of Spring Chinook”


--CBB, July 15, 2016, “NOAA Re-Authorizes States To Lethally Remove Salmon-Eating California Sea Lions At Bonneville Dam,”


--CBB, June 17, 2016, “Final 2016 Pinniped Report: Sea Lion Salmon Take Astoria To Bonneville Dam Could Be 20 Percent Of Run,”

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