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ODFW Analysis: With Continued Sea Lion Predation Willamette Winter Steelhead At Risk Of Extinction
Posted on Friday, August 11, 2017 (PST)

Upper Willamette River winter steelhead were listed as threatened under the federal endangered species act in March 1999 due to the impact on the native fish by federal dams and habitat loss. Harvest of the fish has not been allowed for more than 20 years.


Now add as a major threat to the steelhead male California sea lions picking off 25 percent or more of the wild run at Willamette Falls.


The accumulated impacts and particularly predation by the sea lions, according to a recently released Oregon Department of Fish and Wildlife analysis, is placing the iconic fish at a high risk of extinction.


The number of wild winter steelhead returning to tributaries in the upper Willamette River has been declining for a decade, ODFW says. The return this year was the lowest on record, with 822 fish getting past Willamette Falls, but just 512 of those are native winter steelhead. The remainder are a self-sustaining population derived from a hatchery program that was discontinued decades ago, according to Dr. Shaun Clements, senior policy advisor with ODFW. These additional fish turn into west-side tributaries, such as the Yamhill and Tualatin rivers.


“ODFW scientists found that sea lions consumed at least one quarter of the wild steelhead run and warned that if sea lion predation continues at these levels, there is an up to 90 percent probability that at least one wild steelhead population of four populations will go extinct as a direct result of the predation,” ODFW said in an August 7 news release. “The near-term risk of wild steelhead extinction can be significantly reduced or avoided by limiting sea lion access to Willamette Falls.”


“We know what the problem is and have seen this coming for about a decade, we just couldn’t take action to prevent it,” said Clements.


ODFW says the action needed to prevent Willamette wild winter steelhead’s slip into extinction is to remove some or all of the sea lions.


Two conservation groups believe that another factor for the decline in numbers of the upper Willamette River winter is the improper use of hatcheries that produce non-native summer steelhead and that those fish compete with the wild winter run because they share habitat. The Conservation Angler and the Willamette Riverkeeper sued the U.S. Army Corp of Engineers in May asking the agency to stop producing the summer fish at Corps-owned Marion Forks and South Santiam hatcheries until it completes an ESA consultation with NOAA Fisheries. The hatcheries are operated by ODFW.


(See CBB, June 9, 2017, “Groups Sue Corps Over Upper Willamette Summer-Run Steelhead Hatchery Releases; Says Harm Wild Fish,”


To combat the damage to fish runs by sea lions, ODFW began hazing the pinnipeds at the falls in 2009. It is now preparing a Section 120 permit application that it will send to NOAA Fisheries this month. The permit would allow the state to lethally remove a certain number of the sea lions each year.


(See CBB, July 14, 2017, “Ocean Conditions, Sea Lions Faulted For Low Willamette Steelhead Return; Only 822 Wild Steelhead,”


“Removal of a few problem individuals will have no impact on the overall sea lion population but can significantly benefit ESA-listed fish,” said Robin Brown, lead scientist for ODFW’s marine mammal program.


Any solution to address the threats to wild fish populations will have to strike a balance between recovery of the imperiled steelhead and the ongoing conservation of sea lions, according to ODFW.


Also at stake are significant regional investments in recovery efforts, such as improvements in fish passage at dams, restoration of fish habitat, and implementation of fishing regulations that prohibit anglers from harvesting wild fish. ODFW scientists have determined that curtailing the immediate impact created by sea lion predation is essential to saving the steelhead from extinction to support the success of long-term recovery efforts.


“Striking an appropriate balance between the recovery of ESA-listed salmon and steelhead populations and the ongoing conservation of sea lions is essential,” Clements says in his July 31 analysis. “Without restoring this balance, the multi-billion dollar regional investment in recovery efforts to address issues with habitat and dams are at high risk of failure and some fish populations, such as Willamette steelhead may be lost.”


Sea lions are not listed under the ESA, but they are protected under the federal Marine Mammal Protection Act. However, unlike the ESA, the MMPA has “fewer tools for managers to use to balance the conservation of predators and prey and prevent these situations in locations where fish are most vulnerable,” ODFW says.


Sections of the MMPA were revised in 1994 to allow limited take of sea lions to protect ESA-listed salmon and steelhead, but that includes processes that take a long time to enact.


“Experience over the last 20 years has shown that these delays place fish stocks in danger of extinction, and result in the need to remove far more sea lions than if proactive management were allowed in certain cases,” the analysis says. “Ultimately, there is an urgent need to provide more flexibility in Section 120 of the MMPA to allow for more proactive management.”


That’s why the agency is also supporting federal legislation that, it says, would balance sea lion predation with ESA needs.


“We are in on-going discussions with state and tribal fishery managers and several stakeholder groups,” Clements said. “Given the situation at Willamette Falls, everyone is united in their call for swift action, and ODFW stands ready to provide expertise to the Northwest congressional delegation on a bipartisan, compromise bill to revise the MMPA to address these emergency situations without undermining the strength and importance of this law.”


Bills in the House and Senate; H.R. 2083 is sponsored by Rep. Jamie Herrera Beutler (R-Wash.) and Rep. Kurt Schrader (D-Ore.), and S 1702 is sponsored by Sen. James Risch (R-Idaho. The House bill has cleared the Natural Resources Committee.


(See CBB, July 28, 2017, “Bill To Expedite Sea Lion Removal Clears House Natural Resources Committee, Heads To Floor,”


Given the current predation rate and low returns of the steelhead, Clements’ analysis predicts an almost 90 percent chance that at least one of the four populations of wild winter steelhead will go extinct within 100 years.


Without sea lions present, the North Santiam River population has a 2 percent chance of extinction, according to the analysis. The South Santiam population has about a 5 percent chance of extinction, while the Molalla population has a 0 percent chance.


However, with the sea lion presence, the chance for extinction in the next 100 years rises dramatically. At a low predation rate, such as that observed in 2015, the chance for extinction in the North Santiam is 8 percent, 16 percent in the South Santiam and 0 percent in the Molalla. At an average predation rate (2016), the chance of extinction in each of the rivers is 27 percent, 34 percent and 2 percent. At a high predation rate like this year, the chance of extinction in each of the rivers is 64 percent, 60 percent and 21 percent. At all levels of predation, the Calapooia River is most at risk of extinction, with chances all near 99 percent.


The chance that none of the three populations will go extinct is lowest with no sea lions present (94 percent) and highest if predation follows this year’s trend (11 percent chance of at least one population going extinct, but the reverse of that is that there is an 89 percent chance that at least one population will go extinct).


“We are at a point where any more delays in the Willamette may condemn this run to extinction,” Clements said. “We need to act now or extinction may be our legacy.”


California sea lions have expanded along the West Coast over the past four decades to a population of nearly 300,000 animals coast-wide today, ODFW says. As numbers increased, a small proportion of sea lions – all males – have expanded their range into freshwater areas where migrating salmon and steelhead are especially vulnerable, including in places such as Ballard Locks in Washington, Bonneville Dam and at Willamette Falls where fish tend to congregate before moving upstream. At these locations, predation by sea lions is especially high and adversely impacts salmon, steelhead, and sturgeon. In the 1980s, sea lion predation on winter steelhead at Ballard Locks in Seattle effectively destroyed the Lake Washington stock.


Also see:


--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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