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Invasive Northern Pike Population In Lake Roosevelt Growing; Eradication Funding Running Low
Posted on Friday, April 14, 2017 (PST)

The number and size of northern pike found in Lake Roosevelt, the reservoir backed up behind Grand Coulee Dam, is growing and so too is the determination of tribes and the state of Washington to eradicate the voracious and invasive species, but they may be running out of the funds needed to continue their eradication work.

 

Northern pike are a threat to nearly every species they encounter. Predation by pike on smaller fish imperils efforts to raise and release trout, kokanee, and other game fish into the lake. If they continue to proliferate in Lake Roosevelt., they could eventually find their way downstream beyond the dam and into the Columbia River where they could threaten populations of threatened and endangered salmon and steelhead.

 

Even if they can be contained in the lake, but not eradicated, they could eventually threaten anadromous fish that tribes hope to reintroduce upstream of Chief Joseph and Grand Coulee dams. A habitat assessment by the Spokane Tribe of Indians, partly paid for by the Northwest Power and Conservation Council and Bonneville Power Administration cost-savings funds, is underway. The $200,000 study is assessing whether reintroducing salmon and steelhead into waters upstream of Grand Coulee Dam is feasible as it researches the potential habitat available to support spawning and juvenile rearing.

 

(See CBB, April 15, 2016, “Council Votes To Move Forward On Salmon/Steelhead Habitat Assessment Above Grand Coulee,” http://www.cbbulletin.com/436490.aspx)

 

But the proliferation of larger northern pike could threaten that and the funds to continue eradicating the invasive species is uncertain, said Laura Robinson, program implementation and liaison specialist with the Council’s Fish and Wildlife staff, at the Fish and Wildlife Committee meeting in Missoula Tuesday, April 11.

 

“Last year, during a 16-week season, 114 adults were caught,” she said in a follow-up email. “This year, in the 6.5 weeks they have been netting so far, 702 adults have been caught. All in the Kettle Falls area.”

 

Gillnetting to study and eradicate the species from the lake began last summer. Researchers from the Washington Department of Fish and Wildlife, the Spokane Tribe of Indians, the Kalispel Tribes and the Confederated Tribes of the Colville Indians have been out gillnetting to reduce the northern pike population in the lake.

 

The gillnetting is also part of a long-term study to keep track of the number and locations of pike in the lake.

 

“STI, CCT, Kalispel, and WDFW are all working on the eradication work,” Robinson said. “At this point we are unsure about funds and the extent of the work they will be able to do this year.”

 

She had offered a quick update at the Fish and Wildlife meeting to “signal the problem for them and give them a heads up that we may hear more about funding needs for it in the future. There will be a presentation to the Council in July on the work being done.” That presentation will be headed up by Washington Council member Guy Norman.

 

Recently biologists caught a 20-pound female who had gorged on smaller fish. Her gonads, which were full of eggs, weighed in at 2.2 pounds, according to a blog called “Nightmare Fish” by John Harrison on the Council’s website (https://www.nwcouncil.org/news/blog/northern-pike-update-march-2017/).

 

“They eat crayfish. They eat suckers. They eat bass, trout, Walleye, Perch, Lake Whitefish, juvenile White Sturgeon, mice, and baby ducks. They even eat their own young,” Harrison wrote.

 

“They eat everything,” said Holly McLellan, principal fish biologist for the Colville Confederated Tribes. “We need to stop pike from moving downstream now.”

 

The pike in Lake Roosevelt likely migrated down the Pend Oreille River, which enters the Columbia just north of the international border. The Kalispel Tribe and WDFW have been aggressively removing pike in the Pend Oreille River since 2007 and have been successful in Box Canyon Reservoir. They are now focusing their efforts in Boundary Reservoir, all in an effort to stop the downstream spread of this invasive species, Harrison wrote.

 

Norman recently visited Lake Roosevelt and spoke with Colville and Spokane tribe biologists as they netted pike.

 

“I was amazed by the number of adult pike they were catching with so little effort,” Norman said in Harrison’s blog. “It certainly rang the alarm bells for me. This is something that could have significant ecological effects on the lake, and on fisheries both in the lake and downriver. We need to get on top of it.”

 

To improve understanding of the population in Lake Roosevelt, every other week this year since February, biologists with WDFW and the tribes have been netting pike in the shoreline shallows around the Colville and Kettle rivers, where the fish school in preparation for spawning in May and early June. It’s part of an effort that began last year, even though the first pike was discovered in the lake in 2009.

 

In addition to Council support last year for pike eradication, the Colville Tribes have been funding suppression efforts through their Columbia River Fish Accord with BPA and with internal tribal funds.

 

There is no doubt pike numbers are higher this spring than during the same period last year, McLellan said.

 

Through mid-March, 326 were caught ranging in size from 12 to 42 inches and averaging 17 inches and 2 pounds per fish, or about 10 times more than were caught during the same period in 2016.

 

The research fishing will continue through early June when spawning will be over and the fish will move into deeper water, according to the blog. Next fall, researchers will electro-fish and gillnet the shorelines, as they have in recent years, to assess and remove the population of juvenile pike.

 

Meanwhile, the Colville Tribe and WDFW have established monitoring stations downriver in Lake Roosevelt, in Lake Rufus Woods behind Chief Joseph Dam, in the Okanagan River, and in Banks Lake, the reservoir above Grand Coulee that supplies irrigation water to the 600,000-acre Columbia Basin Project. Water samples will be tested for pike DNA that would serve as an early warning that the predators, even a small number of them, are present so that eradication efforts could begin quickly.

 

“The population will keep expanding if we are not aggressive enough with the removal,” McLellan concluded.

 

Also see:

 

--CBB, September 23, 2016, “Council OKs More Funds For Fighting Pike Invasion: ‘Pike Pose Enormous Threat To Salmon, Steelhead,” http://www.cbbulletin.com/437602.aspx

 

--CBB, May 20, 2016, “Considering Predation Levels When Reintroducing Salmonids Above High Head Dams,” http://www.cbbulletin.com/436761.aspx

 

--CBB, March 11, 2016, “Council FW Committee Moves Forward On Salmon Reintroduction Study Above Grand Coulee,” http://www.cbbulletin.com/436211.aspx

 

-- CBB, January 15, 2016, “Council Considers More Money For Pike Removal: ‘An Alarming Increase In Pike Abundance,” http://www.cbbulletin.com/435860.aspx

 

-- CBB, December 18, 2015, “Council Moves Proposal For Evaluating Salmon Habitat Above Grand Coulee To Science Review,” http://www.cbbulletin.com/435731.aspx

 

-- CBB, Nov. 19, 2015, “A Northern Pike Caught In John Day Reservoir: For Salmon, Canary In The Coal Mine?” http://www.cbbulletin.com/435580.aspx

 

-- CBB, October 16, 2015, “Can Salmon, Steelhead Survive Above Grand Coulee Dam? Council Investigation May Provide Answer,” http://www.cbbulletin.com/435273.aspx

 

-- CBB, September 18, 2015, “Council Moves Ahead With Plan To Assess Potential Salmon Habitat Blocked By Grand Coulee,” http://www.cbbulletin.com/435022.aspx

 

-- CBB, July 17, 2015, “Invasive Northern Pike Spreading Further, Reproducing; Council Hears Information On States’ Policies,” http://www.cbbulletin.com/434535.aspx

 

-- CBB, Jan. 16, 2015, “Tribes Lay Out Process For Investigating Feasibility Of Salmon Reintroduction Above Grand Coulee Dam” http://www.cbbulletin.com/432935.aspx

 

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