Invasive and voracious, northern pike are inching closer to salmon habitat, but Washington plans to fight the threat

Thousands of northern pike have been removed from the Box Canyon reservoir since 2012. - KALISPEL TRIBE PHOTO
Kalispel Tribe photo
Thousands of northern pike have been removed from the Box Canyon reservoir since 2012.

Salmon face many threats these days, from warming water and difficult passage over dams, to diminished habitat for spawning.

Washington, along with federal, local and tribal governments, has already spent millions of dollars trying to address those issues. But now there's an even newer threat that could stand to wipe out entire populations of salmon in the blink of an eye: northern pike.

Invasive, carnivorous, voracious and all around mean looking, the northern pike poses an immediate threat to other species in water bodies where it's introduced. As an apex predator, it's a fish that lives for one reason: to eat other fish. But it's not picky either. Pike will also eat baby ducks, frogs, even each other.

Pike have decimated other species in stretches of the Pend Oreille River, where the few fish types remaining after dams were installed last century — such as bull trout, west slope cutthroat, and mountain white fish — happen to appeal to the invasive pike.

"If you're shiny and have soft fins, usually you're the first to go," says Joe Maroney, director of fishery and water resources with the Kalispel Tribe's Natural Resources Department.

Early counts of the fish (started around 2004) put the population around 400 in the Box Canyon Reservoir, south of Metaline Falls, but within five years, the pike population had exploded to more than 10,000, Maroney says. Meanwhile, other fish dwindled.

The good news is the Kalispel Tribe, in conjunction with the state Department of Fish and Wildlife, has been quite successful in suppressing pike through netting efforts.

Even better, pike haven't yet gotten into the state's "anadromous zone" where migrating fish like salmon swim upriver to spawn on the Columbia and Snake rivers.

The bad news is that pike are now in Lake Roosevelt, the water body behind Grand Coulee Dam. Only that and Chief Joseph Dam separate the invasive species from areas where salmon spawn, and experts say that pike migration down the Columbia must be avoided at all costs.

So Washington's wildlife agency and invasive species council are looking to up the ante, potentially voting next month to classify the fish at the highest prohibited level (similar to invasive mussels) and getting ready for a rapid response to the invasive threat should they cross into that zone.

"Northern pike are a problem, not an opportunity," says state fish biologist Randy Osborne, whose district covers Spokane, Lincoln and Whitman counties. "Really it's not a waiting game. If those fish get into a system, you'd better pay attention to them now and take measures to correct it."

Northern pike are native to some parts of the Northwest, notably parts of Alaska and one region in Montana.

But elsewhere, they have been illegally introduced, most likely by anglers transporting the fish and putting them into water bodies in hopes they will produce big sport fish, Osborne says.

"It's my opinion that any time a fish is illegally introduced and jockied around, it's a pretty selfish act," Osborne says. "I can't even venture a guess as to why, other than if somebody liked fishing for pike, which they are a popular species to catch."

Pike can easily grow to be about 2 feet long, but have been recorded up to 5 feet long, and into the area of about 40 or 50 pounds.

"It's nothing at all for a northern pike to eat a fish that is two-thirds of its length," Maroney says. "It's got a big mouth with lots of little tiny teeth that it can grab on with."

Pike also reproduce rapidly, which Kalispel Natural Resources saw firsthand when the fish were discovered in the Box Canyon Reservoir.

Knowing something needed to be done, the tribe set to work studying the population and working on suppression efforts. While they tried electrofishing and seining (which involves using large nets), gill netting quickly proved to be the most successful and least harmful to other fish, Maroney says.

Over the years it became clear that the best time to net was right at ice-out, when the surface of sloughs are thawing out, so the pike could be caught just before spawning there, and other fish caught in the nets would have a high survival rate, he says.

"One of the main reasons we start doing it right at ice-out is the fish are pretty lethargic," Maroney says, "so the survival rate is greater than 90 percent when we release them."

In 2013, their work removed 6,452 northern pike. The captured number dipped dramatically each year, hitting 181 in 2016.

"To use an analogy, we've got the grass mowed as short as possible and we want to keep it as short as possible."

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By 2017, netting removed only 34 northern pike, making it clear the efforts to knock down the population were effective. However, in 2018 and 2019, there was a spike back upward in the pike population, with 271 caught in 2018 and 427 caught this year. (The most recent report to Fish and Wildlife officials hasn't been posted yet.) Still, Maroney says that their efforts should give hope.

"I would say we're pretty excited on the success that we've had on it so far," Maroney says. "To use an analogy, we've got the grass mowed as short as possible and we want to keep it as short as possible. ... We understand that it's an effort we're going to have to continue for quite some time."

To avoid pushback from people who knew that pike are tasty, the tribe initially donated its catch to a food bank. But testing shows pike often far exceed safe levels of heavy metals, so the tribe stopped sharing the catch.

Now, after more than a decade of talking about the serious threat pike pose, Maroney says he's happy to see others around the state taking the issue more seriously.

"When pike were just in the Pend Oreille, people didn't really care that much, not to be too flippant," Maroney says. "It's only really starting to gain momentum, I would say over the last couple of years, where people are recognizing, 'Oh man they're in Lake Roosevelt now, they're causing problems, and they're moving farther downstream, not far from Grand Coulee Dam, which means not far from the salmon and steelhead zone."

In the middle of a multiday marathon meeting on Friday, Sept. 13, the Washington Fish and Wildlife Commission hears from staff about aquatic invasive species.

First, there's an update on the vessel-inspection sites looking to prevent the introduction of invasive mussels, which can pose serious economic threats if they get into drinking water supplies and damage infrastructure.

Next, the commissioners hear a proposal to list northern pike as a "prohibited level one" species, instead of its current level-three status, which would put it on par with those invasive mussels.

It's recognized that invasive mussels can cause billions of dollars in damage if they enter the right waterways. While there isn't an economic analysis for pike yet, Maroney says some back-of-the-napkin math can easily estimate damage into the tens to hundreds of millions per year if salmon and steelhead fisheries were impacted.

"We can all see a day where these fish are inching toward the anadromous zone," state fish biologist Eric Winther tells the commission during its meeting. "What we're asking is to move that from a prohibited level three up to prohibited level one. The gist is establishing building blocks toward what's probably inevitable. That will help us deal with slowing that down and step up our game tremendously."

Indeed, governments including the Spokane and Confederated Colville tribes, as well as public utility districts along the Columbia, are already looking at what rapid response plans might look like, Osborne says.

Those groups came together earlier this year in May, along with the Kalispel, to do an "all-hands" pike removal in Roosevelt. That effort gathered about 450 pike, Winther tells the commission.

The commissioners ask about other predators that have already gotten into the anadromous zone, such as bass and walleye. Winther says while those predators are important, pike present a special threat.

"It can take a lot of resources to manage an existing problem," Winther says. "It takes a lot fewer resources to manage an emerging problem."

Maroney, who also sits on the invasive species council, reinforces that point to the commission.

"Seeing what [this] species can do as far as on the landscape and the ecosystem is absolutely scary," Maroney says. "Raising it to the prohibited level one raises awareness this is a serious issue." ♦