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Ocean Conditions, Sea Lions Faulted For Low Willamette Steelhead Return; Only 822 Wild Steelhead
Posted on Friday, July 14, 2017 (PST)

The 2017 run of summer hatchery-produced steelhead in the Willamette River is arriving in numbers lower than expected, but the wild winter run of steelhead, listed as endangered under the federal Endangered Species Act, arrived in even smaller numbers and that could impact its recovery.

 

The count of summer hatchery steelhead that passed Willamette Falls at Oregon City as of July 7 was 1,783 fish, according to the Oregon Department of Fish and Wildlife fishway count (http://www.dfw.state.or.us/fish/fish_counts/willamette/2017/2017_Monthly_sheet.pdf), January to July (summer steelhead are counted at the Falls through July).

 

The final count for the 2017 run of winter steelhead over the falls was just 822 fish: the average is seven times more, about 5,600. While those fish have already spawned, the actual population estimate isn’t yet available as ODFW is still processing redd data.

 

The low returns this year are likely due to poor ocean conditions, according to ODFW’s Shaun Clements, senior policy advisor for the agency’s fish division. But there are indications that sea lions that camp out at Willamette Falls early in the run are taking a toll on the wild winter steelhead.

 

With just 822 of the endangered fish making it over the falls, the low number of endangered winter steelhead translates to an even lower distribution of the fish into Willamette River tributaries where they spawn.

 

Numbers have yet to be finalized, Clements said. However, given the 822 wild winter steelhead that passed the falls and if they dispersed to tributaries in a similar pattern as past years, some 113 of the wild fish turned into the North Santiam River, 158 into the South Santiam River, 38 into the Calapooia River and 203 into the Molalla River. The remainder, he said, go into tributaries on the west side of the Willamette River and a few go into the upper Willamette River.

 

“There has been a coast-wide decline in winter steelhead numbers because of the poor ocean conditions, but the Willamette has been particularly hard hit,” he said. “Historically, the Willamette ESU (evolutionary significant unit) and Clackamas population tracked pretty well in terms of abundance, though there were far more fish in the Willamette. More recently, during the period when sea lion predation has increased at the falls, we’ve seen the Clackamas do a lot better than the Willamette.

 

“Unfortunately, even though run sizes have decreased at the falls and we might expect sea-lions to have a harder time finding/catching winter steelhead, they have still been able to capture a significant proportion of the winter steelhead population,” Clements said.

 

In late June, Clements said that some 20 to 25 percent of wild winter steelhead that had passed the falls this year were taken by California sea lions as the fish entered the fish ladder. Observers at the falls had documented sea lions eating about 200-250 of the winter fish.

 

He noted that although sea lions had been at the falls since the 1990s, predation became an issue in 2009 and average annual run sizes over the falls seems to confirm Clements’ suspicion that sea lions are exacting a larger toll on winter steelhead.

 

For example, prior to 2009, the average annual run of winter steelhead heading to the North Santiam River was 1,178 fish, but after 2009 it dropped 35 percent to an average run of 761 fish. A similar decline has occurred in the Mollala River where the pre-2009 average was 1,703 fish, dropping 28 percent to 1,235 fish after 2009.

 

The South Santiam and Calapooia rivers are experiencing the greatest declines. The pre-2009 South Santiam run averaged 1,636 fish, but has since dropped 55 percent to 733 fish, and the pre-2009 Calapooia run averaged 378 fish, dropping 53 percent to 176 fish.


"Additionally, we’ve been comparing the Willamette and Clackamas population, the latter doesn’t experience the same level of predation,” Clements said. “While those populations have tracked in the past, since 2009 when we think predation started ramping up we are seeing a different pattern emerge.”


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

 

“At present there are about six sea lions that are having the greatest impact, so we would look to remove these first,” Clements said in June. “Ultimately, there are approximately 40 individuals present at Willamette Falls and the number is growing. Our experience over the past decade suggests that it would be far better on the fish and the sea lions if we could intervene early and prevent the learned behavior that results in additional sea lions recruiting to locations like Willamette Falls.”

 

At this time of the summer, ODFW is not contemplating retention restrictions on anglers for winter steelhead since they have already spawned and left the tributaries. And, when the winter steelhead are in the river, Clements said, it is not legal to keep any unclipped steelhead.

 

“We don’t plan any additional angling regulation changes to protect this population at present as they have spawned and left the tribs,” he said. “River conditions were so high during peak spawning in March-April this year that these fish were well protected. We will look at the situation again for next season and see if additional action is needed given flows, run projections, and sea lion presence.”

 

Some conservation groups believe that the summer steelhead hatchery program has a negative impact on the wild winter run of steelhead and should be stopped or at least changed to protect the winter fish. In May, two groups – The Conservation Angler and the Willamette Riverkeeper – sued the U.S. Army Corps of Engineers, alleging that releasing hatchery produced summer run steelhead from its hatcheries in the upper Willamette River endangers wild winter steelhead.

 

Also see:

 

--CBB, June 23, 2017, “Oregon To Seek Permit To Lethally Remove Salmonid-Eating Sea Lions At Willamette Falls,” http://www.cbbulletin.com/439150.aspx

 

-- CBB, June 9, 2017, “Groups Sue Corps Over Upper Willamette Summer-Run Steelhead Hatchery Releases; Says Harm Wild Fish,” http://www.cbbulletin.com/439056.aspx

 

-- CBB, March 10, 2017, “Corps Report: Sea Lions In Bonneville Dam Tailrace In 2016 Consumed 4.5 Percent Of Spring Chinook” http://www.cbbulletin.com/438453.aspx

 

--CBB, July 15, 2016, “NOAA Re-Authorizes States To Lethally Remove Salmon-Eating California Sea Lions At Bonneville Dam,” http://www.cbbulletin.com/437133.aspx

 

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