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Fighting The Northern Pike Invasion Into Basin: Spokane Forum Calls Economic Impact Study A Priority
Posted on Friday, July 27, 2018 (PST)

A movement is underway to pursue a comprehensive study of the potential economic impacts that could come with an advancing northern pike invasion across the Columbia Basin river system, including salmon waters referred to as “The Anadromous Zone.”


The study emerged as a priority during a well-attended forum on pike in the Pacific Northwest that was held Tuesday and Wednesday in Spokane. The forum was held in conjunction with the 28th annual convention of the Pacific Northwest Economic Region (PNWER) at the Davenport Grand Hotel.


The forum, attended by more than 60 people, resulted in a consensus to pursue the economic impact study, along with establishing a U.S.-Canadian committee on pike, and a resolution to advocate for more funding to curb the proliferation of pike, a voracious predator repeatedly described as an eventual threat to protected salmon species.


Justin Bush, executive coordinator of Washington’s Invasive Species Council, said the intent is to conduct a “PNWER-scale” economic impact study, meaning it will be regional, including British Columbia and Alaska, where pike have had devastating effects on salmon runs in the south-central part of that state. Because of its regional nature, the study would be funded through considerable cost-sharing and it would be coordinated by the Pacific Northwest Economic Region.


Brian Heise, Bush’s counterpart on a British Columbia Invasive Species Council, said the PNWER executive committee will decide, probably in a month, whether to pursue the study as recommended by the forum


Bush said there is potential for the Northwest Power and Conservation Council to re-activate an Independent Economic Advisory Board specifically to participate in development of an economic impact study. He said Washington Council member Tom Karier has committed to exploring that possibility for an advisory board that has assisted in past economic reviews but has not been recently active.


While there are aggressive efforts to suppress pike populations and prevent them from spreading in the Pacific Northwest, forum participants said it is just a fraction of the effort that may be needed in the future. And that’s why an economic impact study is considered crucial — to inform the public and policy makers who control purse strings about how costly an advanced pike invasion could be.


Joe Maroney, a fisheries manager with the Kalispel Tribe, pointed to the success of a campaign that made use of an economic analysis projecting the costs of allowing invasive quagga and zebra mussels to proliferate throughout the region. “Really, it wasn’t until the economic analysis that came out with $500 million annually and what that means to ratepayers, what it means to infrastructure, what it means for water supplies.”


After that, a coordinated effort emerged among northwestern states, most notably with public education and strict watercraft inspection sites along highways throughout the region.


(See CBB, Sept. 6, 2013, Report Says Spending Millions On Zebra/Quagga Mussel Prevention ‘Economically Justified’ The 2013 report, “Economic Risk of Zebra and Quagga Mussels in the Columbia River Basin” is available at


During a presentation to the forum, “Lessons Learned From the Pend Oreille River: We Can Do This,” Maroney referred to a “bar napkin” calculation that he did, based on a model used to develop a pike economic impact study that was carried out in California.


His calculation came to $33 million annually for the state of Washington alone, if pike were to become established in waters they have yet to invade. The point of his estimate is that it is probably close to accurate, but it is a crude estimate.


There are many economic impacts that weren’t even considered in his estimate, such as potential costs to public utilities, or the costs for re-licensing dams with provisions to protect native fish, including threatened species. Dam licenses are already loaded with millions in those costs, but they would escalate. That’s not to mention millions that have already invested in habitat improvements and other measures to boost native fish populations.


Bush noted there would be costs for hydropower ratepayers, and costs would continue to ripple into areas such as the loss of tribal fishing for commercial, sustenance or cultural reasons.


“These direct and indirect impacts, we kind of know that will happen, but in terms of quantifying it in a scientific way, that’s really what we’re trying to get at,” he said.


Fisheries managers like Maroney are not waiting around for an economic impact study; they have been engaged in pike suppression efforts for years.


“We’ve been dealing with it for about 15 years,” Maroney told the forum about work that has been underway since pike were first detected in the Pend Oreille lake and river system.


Maroney described the effects of a “full-blown” suppression program that got underway in 2012, after the Washington Fish and Wildlife Commission declared pike a “prohibited” species and a pilot project was conducted in the Pend Oreille River’s Box Canyon Reservoir.


Mostly through targeted gill netting and electro-fishing, about 6,000 pike were removed in 2012; 6,500 in 2013; 4,000 in 2014; 750 in 2015; and by 2017, just 34 pike were removed.


Maroney said the sharp decline over a five-year period shows the effectiveness of intensive gill netting that was gradually tapered down to match the declining catch.


“There were a lot of people in the Columbia Basin who thought, ‘there’s no way you can do it,” Maroney said. But the total catch so far comes to about 17,500 pike, and their chances of becoming permanently established have become sharply reduced.


Jim Baker of the Washington Department of Fish and Wildlife said the Box Canyon Reservoir project is a good example of what can be done elsewhere, but an equal effort would require about 10 times the funding necessary to have similar results in Lake Roosevelt above Grand Coulee Dam.


Pike were first discovered in the upper reaches of that reservoir in 2009, and by 2015 anglers were catching the fish near Kettle Falls. Baker said the Colville and Spokane tribes have led the way in a coordinated suppression effort that just got underway, netting 4,800 pike in the Kettle Falls area last year. By the end of June of this year, 1,164 pike had been removed.


Baker bluntly said more needs to be done on a reservoir that is much larger and more dynamic than the Box Canyon Reservoir. The underlying current strategy is to basically turn down the water spicket, reducing the number of pike from a gush to a trickle.


Waters below Grand Coulee Dam are considered “The Anadromous Zone,” and Baker said pike will eventually turn up in those waters, whether they are drifting past the dam or they are being transported in a pickup truck.


“My gut says, ‘when, not if,’” he said. “There is always potential for pike to sort of hop-scotch down the basin.”


Public education is crucial, Baker said, but he noted that Public Utility Districts downstream are already engaged in alerting anglers to report any pike catches.


Other strategies and endeavors targeting pike were discussed at the forum.


Kellie Carim, a scientist with the U.S. Forest Service’s Rocky Mountain Research Station in Missoula, presented the results of genetic analysis that aimed to identify source populations of fish in Pend Oreille River, Box Canyon Reservoir and Lake Roosevelt, all located in eastern Washington. She compared the fish in eastern Washington to a total of six potential source populations: Thompson Falls Reservoir (MT), Noxon Reservoir (MT), Cabinet Gorge Reservoir (MT), Lake Pend Oreille (ID), Coeur d’Alene Lake (ID) and Cave Lake/Medicine Lake (ID). 

The results of the genetic data indicate that of the six potential source populations, pike in eastern Washington most likely originated from Cave Lake/Medicine Lake, which are part of the chain lakes upstream of Lake Coeur d’Alene in Idaho. Given the pattern occurrence and spread of pike in eastern Washington, these results suggest that fish were moved overland by people from the Coeur d’Alene drainage, rather than swimming through connected waterways. Carim is seeking to expand the number of source populations to identify any other potential sources that may have contributed to the current invasion in eastern Washington.

Speakers discussed varying levels of success with pike suppression methods ranging from bounties for pike, regulations requiring anglers to kill pike they catch, gill netting and perhaps a newer direction targeting pike habitat.

University of Montana professor Peter Rice talked about an invasive aquatic plant called flowering rush, which provides pike with optimal habitat for spawning and ambush predation. He pointed to his research in the Montana’s Flathead River in the sloughs just upstream from Flathead Lake that are choked with flowering rush and a pike population that has become well-established despite having no regulatory protections.


Montana Fish, Wildlife and Parks conducted a multi-year study of pike predation in the lower Flathead River, determining that pike consumed 13,400 cutthroat trout and 3,457 threatened bull trout during course of the study. Rice’s work examined the habitat in the study area, finding that thick, weedy flowering rush was prevalent in areas where pike dominated. He also pointed out how expanses of flowering rush emerge — de-watered  — as reservoirs in the Columbia Basin drop to low-pool during the winter months.


Rice suggested that efforts to curb flowering rush might have tangential benefits in reducing the viability of pike populations.


Also see:


-- CBB, May 11, 2018, “Pike Suppression Efforts, Costs to Rise As Managers Fight To Keep Fish from ‘Anadromous Zone,”


--CBB, February 16, 2018, “Scientists Want More Detailed Information On Northern Pike Suppression Plan In Lake Roosevelt,”


--CBB, July 21, 2017, “Lake Roosevelt Northern Pike Numbers Rise; ‘Chronic Recruitment, Exponential Growth’,”


-- CBB, June 23, 2017, “Invasive Northern Pike Spreading In Lake Roosevelt; Tribe Seeks Funds To Expand Removal Efforts,”


--CBB, September 23, 2016, “Council OKs More Funds For Fighting Pike Invasion: ‘Pike Pose Enormous Threat To Salmon, Steelhead,'”


-- CBB, January 15, 2016, “Council Considers More Money For Pike Removal: ‘An Alarming Increase In Pike Abundance,”


-- CBB, Nov. 19, 2015, “A Northern Pike Caught In John Day Reservoir: For Salmon, Canary In The Coal Mine?”


-- CBB, July 17, 2015, “Invasive Northern Pike Spreading Further, Reproducing; Council Hears Information On States’ Policies,”


-- CBB, June 12, 2015, “Invasive Northern Pike Threaten Columbia Basin Salmon: Is Four-State Coordinated Effort Needed?”


 -- CBB, April 10, 2015, “Northern Pike Appear To Have Established Presence in Lake Roosevelt,”


-- CBB, Feb. 27, 2015, “Fish Managers Show Success In Keeping Pend Oreille Northern Pike From Moving Into Columbia River”


-- CBB, Dec. 16, 2011, “Washington Gears Up To Stop Non-Native Northern Pike From Invading Columbia Basin Salmon Country”

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