‘Not good for salmon and steelhead’: Smolt-eating walleye worry fishery managers

LEWISTON – Walleye are a prized game fish across much of the Midwest and even in the lower and middle Columbia River.

But fisheries managers on the Snake River see the toothy predator as a scourge – one whose menace is growing as the warm-water species continues to move upstream and deeper into salmon and steelhead territory.

Walleye were found above Lower Granite Dam for the first time in 2016. This summer, anglers are reporting catching them at Heller Bar south of Asotin, deep within Hells Canyon proper at places like the mouth of Rush Creek and even in the lower Salmon River as far upstream as Twin Bridges.

It’s a problem.

“I think we don’t view walleye as a great fishery opportunity, especially up there in what has been the most productive habitat for salmon and steelhead,” said Chris Donley, fish program manager for the Washington Department of Fish and Wildlife at Spokane.

The Snake and its undammed tributaries like the Clearwater, Salmon, Grande Ronde and Imnaha are nurseries and spawning grounds for salmon and steelhead – the undisputed lords of the Pacific Northwest’s free-flowing waterways. The anadromous fish are central to Native American cultures and economies, prized for their fat and protein-packed meat and loved by anglers for their tenacious, head-shaking fights. They serve as wild icons of the region that has desperately tried to hold onto them in a decades-old effort costing billions of dollars.

Annual returns of salmon and steelhead that were once counted in the tens of millions have dwindled to just a tiny fraction of that. Wild runs of the native fish are protected by the Endangered Species Act.

Reasons for their demise are many. Dams with and without fish passage have ruined prime habitat, altered migration timing and water temperatures, and made their journeys to and from the ocean more fraught with peril.

But predation is significant as well. Adults must contend with voracious sea lions in the lower Columbia River. Smolts are picked off by birds like double crested cormorants and caspian terns. Northern pikeminnow, smallmouth bass and now walleye feast on the annual flush of juvenile salmon and steelhead.

Marika Dobos, a regional fisheries biologist for the Idaho Department of Fish and Game, said walleye have the potential to hammer salmon and steelhead populations and it’s important to establish they are unwanted in the Snake River, especially upstream of Lower Granite Dam.

“We are not going to manage this fish as sport fish in anadromous waters,” she said. “They are not good for salmon and steelhead.”

She explained in a recent blog post that walleye were illegally introduced into Lake Roosevelt, behind Grand Coulee Dam on the Columbia River, 80 years ago. Since then, they have migrated down the Columbia River, likely aided by other illegal introductions, and are now in the Snake River.

Dobos wrote the white-fleshed fish are prolific, with average-sized females producing 57,000 eggs annually.

“Once they are established, they are really fecund and they can be really successful in a lot of places,” she said.

While they have been preying on juvenile salmon and steelhead for decades in the lower Columbia, Donley said their presence in the Snake greatly elevates their potential to harm the native fish. In the Columbia, walleye are opportunistic. They devour smolts as the fish are flushed downstream each spring. It’s an all-you-can-eat buffet but one with a limited window.

It’s different in the Snake and its salmon-bearing tributaries.

“When you get walleye into natal tributaries and into areas smolts are rearing prior to outmigration, it’s a whole different thing than eating smolts that are passing by during migration, and the impacts they have to salmon and steelhead abundances are going to be bigger.”

What to do

Idaho, Washington and Oregon have adopted liberal harvest rules on walleye and smallmouth bass alike. In the Snake River system, there are no bag or size limits for the fish and fisheries managers encourage anglers to catch, keep and eat as many as they can.

That likely isn’t enough to affect the population. Becky Johnson, production director of the Nez Perce Tribe’s Department of Fisheries Resources Management, said momentum is building toward pursuing more aggressive actions.

“We are reaching out to co-managers to put together an agreed-upon approach,” she said. “For example, perhaps these fish could be included in the sport reward program.”

For more than two decades, a program funded by the Bonneville Power Administration has paid anglers to catch and turn in northern pikeminnow. Fisheries managers believe the program has reshaped the population of the native fish so there are fewer of the really big pikeminnow that are especially efficient at preying on smolts.

Donley said it is likely impossible to rid the Snake River of walleye, but a sport reward program could be designed to reshape the population and target 14- to 20-inch walleye, the size that really hammers juvenile salmon and steelhead.

“Long term you want to reshape that population to be older and larger. A 30-inch walleye doesn’t want to eat a smolt. It’s going to eat something one-third of its body length which is considerably bigger than a smolt.”

Mark Fritsch, project review and implementation manager for the Northwest Power and Conservation Council, said the pikeminnow sport reward program is due for a revamp and that might make it timely to propose adding other species such as walleye to the mix. Programs vetted by the council are ultimately funded by the BPA. Although the agency has made a concerted effort to scale back on its fish and wildlife financial commitments, Fritsch said a united effort from regional managers might hold sway.

“What needs to happen now is education and transparency on this issue. It would be wonderful to get a letter from the Nez Perce Tribe, Washington and Idaho requesting action,” he said. “That would be really cool.”

The tribe and Washington are receptive. Dobos said Idaho is likely to be but a final decision would come from the agency’s headquarters in Boise.

That leaves only Oregon and it’s not a slam-dunk there. Art Martin, a fisheries manager for the Oregon Department of Fish and Wildlife, said his agency is sympathetic to the angst other agencies feel about walleye. Oregon, however, is not convinced spending money to remove the fish is the best use of limited conservation dollars. Martin said Oregon would likely be on board if Idaho, Washington and the tribe can show there is a conservation benefit to removing walleye.

Easier said than done

Oregon classifies walleye as a game fish. That makes it harder for the state to get behind a walleye bounty program. A decadesold state law forbids the waste of game fish. In the pikeminnow removal program, the fish caught by anglers are collected and disposed of. Martin said that can’t happen with game fish unless it can be proven there is a benefit to doing so.

While it might seem obvious that removing a predator from the mix of threats faced by salmon and steelhead will help them, it’s not necessarily so. That’s because there are so many animals that prey on smolts. Every smolt saved by removing a particular walleye might, in theory, survive to adulthood. But it could be that every smolt, or most of them not eaten by a particular walleye, will be gobbled up by something else like a smallmouth bass, pikeminnow, sea gull or Caspian tern.

“Given the paucity of funding for conservation actions and uncertainty of the conservation value (of walleye removal), we are not convinced that is the highest priority from a conservation perspective,” Martin said.

Oregon would rather spend the money on actions it feels would provide more discernible benefits. He mentioned spilling more water at dams on the Snake and Columbia rivers to aid smolt migration, or even breaching the Snake River dams, as more deserving.

In the meantime, Dobos said Idaho is encouraging anglers to target walleye with the intent that they are helping salmon and steelhead. Most people are catching them incidental to their pursuit of smallmouth bass. Walleye are attracted to lures and baits that imitate prey species. At this time of year, they are in deeper water.

“The closer to the bottom is where people are going to catch them,” she said. “Basically anywhere you are going to find smallmouth bass you have a chance to encounter walleye.”

Eric Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.