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Record Low Steelhead Run Spurs Closures, Reduced Bag Limits; Return Only 30 Percent Of Average
Posted on Friday, September 01, 2017 (PST)

The three states that oversee angling regulations on the Snake River closed the mainstem of the river to retention of steelhead in response to a historically low expected return of the fish.

 

However, some tributaries in Oregon and Washington will remain open where anglers are allowed to retain one hatchery steelhead, while the closure in Idaho is statewide.

 

As of August 28, just 70,000 hatchery and 25,000 wild steelhead had passed Bonneville Dam, just 30 percent of the 10-year average, according to information from the Oregon Department of Fish and Wildlife.

 

The U.S. v Oregon Technical Advisory Committee that forecasts fish runs in the Columbia River basin last met August 14 to review the summer steelhead status. At that meeting, it downgraded the A-run summer steelhead forecast to 54,000 fish (33,000 hatchery fish and 21,000 wild fish) from its pre-season forecast of 122,100 fish. TAC did not review the B-run forecast. That is a later run and is typically just 3 percent complete by this time of summer.

 

The forecast for the combined A/B-Index steelhead return to Bonneville Dam is 119,400 fish, including 41,500 unclipped (34,100 wild) fish. The A-Index forecast is 54 percent and the B-Index forecast is 25 percent of their respective 5-year averages.

 

“Despite the poor outlook, our current estimates suggest enough fish will return to sustain hatchery programs and provide fish for recreational harvest,” said Jeff Yanke, ODFW district fish biologist in Enterprise, OR.  “This is the lowest run we’ve seen in decades, but I’d encourage anglers not to panic and give up on fishing this year. Folks will just need to have a little more patience, and that is one quality steelhead anglers bring to the river.”

 

Anticipating the poor run, Oregon and Washington already had set other restrictions on steelhead fishing, including area-specific, 1-2 month steelhead retention closures and a one steelhead bag limit when retention is allowed in a series of rolling closures that progress upriver following the steelhead return to reduce the take of both hatchery and wild fish.

 

All steelhead (hatchery and wild) must be released as follows:

-- Buoy 10 upstream to The Dalles Dam during Aug. 1-31

-- The Dalles Dam upstream to John Day Dam during Sept. 1-30

-- John Day Dam upstream to McNary Dam during Sept. 1 - Oct. 31

-- McNary Dam upstream to Hwy. 395 during Oct. 1 – Nov. 30

 

Night angling is also prohibited except for registered anglers targeting Northern pikeminnow.

 

(See CBB, June 16, 2017, “States Set Schedule Of Angling Closures Aimed At Protecting Low Numbers Of Wild Steelhead,” http://www.cbbulletin.com/439106.aspx)

 

Upriver summer steelhead pass Bonneville Dam from April through October. Fish passing during July through October are categorized as A-Index or B-Index (also known as A-run or B-run) based on fork length. A-Index are less than 78 cm (about 31 inches) and B-Index are typically more than 78 cm. Passage during July is mainly A-Index fish; B-Index passage normally begins around the end of August. B-Index steelhead primarily return to Snake River tributaries in Idaho, while A-Index steelhead return to tributaries throughout the Columbia and Snake basins, according to the Fact Sheet.

 

Also this week, ODFW opens hatchery fall chinook fishing in the lower Snake River September 1 through October 31 from the Oregon/Washington border with the river to Hells Canyon Dam. The agency anticipates about 27,000 fall chinook this year, which includes 8,000 wild fish. The daily bag limit is six adipose fin-clipped salmon.

 

The poor return of steelhead, both hatchery and wild, has one Idaho biologist asking and answering questions why the run is so small this year.

 

Joe DuPont, Clearwater region fisheries biologist with the Idaho Department of Fish and Game is pointing to poor ocean conditions as the culprit, at least for the A-run of steelhead.

 

In a thoughtful assessment of the lower than average run of summer steelhead (“Why are Idaho’s steelhead runs so low?” https://idfg.idaho.gov/blog/2017/08/why-are-idahos-steelhead-runs-so-low), DuPont said of the A-run of Idaho steelhead, which are mostly hatchery fish, that most of them out-migrated to the ocean during the spring of 2016, spending just one year in the ocean before returning this year.

 

There are a number of factors that influence a juvenile steelhead’s survival and even that can vary depending on if the fish is from a hatchery or is wild, he said.

 

“For example, wild fish typically rear two to three years in fresh water before migrating to the ocean. As such, stream flow, summer and winter water temperatures, habitat conditions, and the number of adults that spawned can all influence survival and the number of smolts that eventually migrate to the ocean.”

 

Still, the number of steelhead smolts that passed Lower Granite Dam on the lower Snake River in 2016 was actually higher than average when compared with 13 years of Fish Passage Center data, he said.

 

While predators (fish, birds and pinnipeds) are a factor in the Columbia River, there were no large changes in predator numbers during the 2016 migration that would explain a downturn in steelhead returns this year, DuPont said.

 

Low river flows also influence survival as juveniles migrate, but the relationship between river flow and smolt survival is difficult to assess due to other changes in the river, such as spill at dams, transportation of fish in barges and the number of predators. However, flows in the Snake River in April and May 2016, during the peak migration, were about average, “suggesting low flows were not responsible for this year’s low A-run return. In fact, if you look at steelhead smolt survival from the Idaho/Washington border downstream to Bonneville Dam, survival appeared about average when compared to the past 20 years.”

 

“If the number of out-migrating smolts was not abnormally low in 2016 (compared to the last 20 years) and flows and survival were about average (for the last 20 years), that leaves ocean conditions as the main driver for this year’s abnormally low return,” DuPont concluded.

 

As far as a ranking of ocean conditions over the past 19 years, he said that 2016 ranked 16 out of 19, meaning ocean conditions were not good for salmon and steelhead, and the amount and type of food that was available in the ocean may be why. See https://www.nwfsc.noaa.gov/research/divisions/fe/estuarine/oeip/figures/Table_SF-02.JPG

 

One of the more important food sources for young steelhead and smaller fish are copepods, but not all copepods are created equal. Northern strains of copepods typically dominate the Washington/Oregon coastal zooplankton community during the summer, DuPont wrote. These tend to be larger and fat-rich providing smaller fish, such as juvenile steelhead and salmon, important calories needed to grow and survive through winter. The southern strains of copepods are smaller and have less fat in them essentially providing fish a “low calorie” diet. Data shows that when northern copepods are abundant, survival of salmon and steelhead goes up, whereas when southern copepods are abundant, survival goes down.

 

“What is very apparent is that in all of 2016, northern copepod biomass was down and southern copepods abundance was up. This doesn’t bode well for salmon and steelhead survival,” DuPont said.

 

Add to the food supply or perhaps one of the reasons for the presence of southern copepods is The Blob, a massive area of unusually warm water that was located off the coast of the Pacific Northwest peaking in 2015 but persisting into 2016 when the juveniles entered the ocean.

 

“Associated with ‘The Blob’ was poor nutrient levels, low biomasses of zooplankton, and warm water species typically not present in northern latitudes,” he said. “These are all factors not favorable to steelhead survival.”

 

“It is obvious that I am pointing at poor ocean conditions for the reason this year’s steelhead A-run is extremely low,” DuPont concluded. “However, I need to emphasize that continued improvements to spawning and rearing habitat and the migratory corridor can make a difference in salmon and steelhead returns. In fact, I would argue that in years like this, if we had better spawning, rearing, and migratory conditions, it could buffer the poor ocean conditions to the point that we could still provide harvest fisheries in Idaho, and wild fish would not be threatened of going extinct.”

 

Oregon Sport Fishing Regulations are at http://www.dfw.state.or.us/resources/fishing/reg_changes/index.asp

 

Information about Washington rule changes can be found at WDFW's website at https://fortress.wa.gov/dfw/erules/efishrules/

 

Also see:

 

--CBB, August 25, 2017, “Fall Commercial Fishing Begins On Columbia, Low Steelhead Numbers Prompts Idaho To Suspend Retention,” http://www.cbbulletin.com/439475.aspx

 

--CBB, July 28, 2017, “Fall Fishing Opens To Lower Than Usual Chinook Returns; Season Includes Rolling Steelhead Closure,” http://www.cbbulletin.com/439345.aspx

 

--CBB, July 21, 2017, “Summer Chinook, Sockeye Runs Downgraded; Treaty Commercial Fishery Extended,” http://www.cbbulletin.com/439313.aspx

 

--CBB, July 14, 2017, “Harvest Managers Approve More Tribal Fishing, Concerns Expressed Over Low Sockeye, Summer Steelhead,” http://www.cbbulletin.com/439267.aspx

 

--CBB, July 7, 2017, “Summer Chinook Fishing Resumes Below Bonneville, Wild Summer Steelhead Passage To Date Very Low,” http://www.cbbulletin.com/439220.aspx

 

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