The front lines in the battle against non-native northern pike invading the Columbia River have moved to the Kettle Falls area of Lake Roosevelt.
Gillnetting that started last year after the confirmation of northern pike spawning at the mouths of the Kettle and Colville rivers has shifted from survey mode to suppression, said Holly McLellan, fisheries biologist for the Colville Tribe.
“Our concern on the Columbia is the same as it was in the Pend Oreille River,” said Bill Baker, Washington Department of Fish and Wildlife fisheries biologist in Colville. “Pike would have major impacts to our native species in Lake Roosevelt, especially redband rainbow trout. And our really big concern is the risk to (salmon and steelhead) fisheries, some of them endangered, below Chief Joseph Dam.”
The state and the Colville and Spokane tribes are working together to figure out the most effective techniques, times and places to kill pike that have successfully spawned for at least two years at the mouth of the Colville River as well as near the mouth of the Kettle River and Singers Bay.
The invasion of northern pike originated from illegal introductions in Montana. The pike found their way down the Flathead River, into the Clark Fork and, by the early 2000s, they were finding ideal habitat in the Box Canyon Reservoir reach of the Pend Oreille River.
The pike were spawning and booming by 2010. The Kalispel Tribe and Washington Fish and Wildlife biologists worked several years developing methods for gillnetting the pike in mass numbers, which started in 2012.
The program was successful to a degree, but some pike continued downstream and into British Columbia where the Pend Oreille flows into the Columbia.
“They were very successful spawning last year in the Columbia, so we’re doubling down our effort this year before the spawning period,” said Holly McLellan, Colville Confederated Tribes fish biologist.
The Colvilles take turns with Spokane Tribe and state Fish and Wildlife staff soaking about a dozen gillnets three nights a week. Since Feb. 21, the netters have taken 362 adult pike, McLellan said Friday.
The trick is to target pike without killing too many of the native fish the fish managers are trying to protect.
“The pike have just started moving into the shallows for prespawn staging,” she said. “This allows us to put nets in the mouth of the Colville to avoid walleye and other by catch.”
Some by catch of walleye and trout have been reported, but most of those fish were removed from the nets and released alive, Baker said.
The by catch involves mostly lake whitefish, which are another nonnative species, McLellan said.
To avoid catching trout that are moving up the Kettle and Colville rivers, the nets are anchored in the shallows away from the currents they follow, she said.
“We’re catching big female northern pike full of eggs,” she said. “The biggest is 21 pounds. They’re averaging 17 inches long.”
While pike were discovered in Lake Roosevelt in 2009, they didn’t catch hold in significant numbers until about three years ago, she said.
“We’re in full pike suppression mode this year,” she said, noting that the Spokane Tribe had kicked into pike suppression last year.
The nets so far have been catching about 10 times more pike than during the same period in 2016.
The Colville Tribe alone has reallocated $200,000 from fisheries mitigation funds to pike suppression plus another $75,000 from tribal funds, she said.
Gillnetting and related research will continue through early June when spawning will be over and the fish will move into deeper water. Researchers will return to the lake in fall to electro-fish and gillnet the shorelines, as they have in recent years, to assess and remove juvenile pike.
DNA and chemistry studies are being launched to track pike and determine if they’re getting farther downstream and into Lake Rufus Woods and the Okanogan River or pumped up into Banks Lake and other areas of the Columbia Basin.
“The tribe is concerned for the salmon fisheries downstream and especially for our native redband trout,which are already declining,” she said.
“No native fishery is safe from the pike,” she said. “They can eat fish up to three-fourths their length. They can disturb the whole ecosystem.”
Stomach contents from the pike caught in Lake Roosevelt have included hatchery rainbows, wild rainbows, kokanee, burbot, suckers, whitefish, juvenile sturgeon, bass, walleye, crayfish, sculpins and other pike as well as ducks and mice.
“They eat everything,” McLellan said.
On the Pend Oreille River, the Kalispel tribe continues its netting pressure on northern pike each spring. Test netting began in 2007 with full suppression starting in 2012 in Box Canyon Reservoir.
“Now we’re in a maintenance mode,” said Nick Bean, the tribe’s pike project manager. He said the number of pike caught last year was low –181 adults from Box Canyon – so the number of nets going out this season is being reduced.
In 2013, the netters caught more than 6,000 pike in the Pend Oreille.
“We expect to catch around 50 this year,” Bean said.
The tribe has expanded its netting downstream into Boundary Reservoir, he said.
The effort started on March 6 this year and will continue through April, he said.
“We feel pretty comfortable that we can stay on top of them in the Pend Oreille.”
British Columbia also has been working to control northern pike in the Columbia, concentrating efforts downstream from Keenleyside Dam to Castlegar, a stretch that includes the conveyor of the problem – the mouth of the Pend Oreille River.
“Pike showed up in the Columbia here around 2010 but weren’t in any abundance until about 2013,” said Matt Neufeld, fisheries biologist for the province.
Gillnetting started in 2012 along with incentive programs that offered anglers cash or entry into cash drawings for turning in pike heads, he said.
On the Pend Oreille River, the Kalispel Tribe sponsored pike fishing tournaments with big cash prizes to help get sportsmen involved in pike suppression.
The Colville Tribe is considering the possibility of offering a $10 reward for pike heads to encourage anglers to harvest pike and expand captures of tagged fish, McLellan said.
Neufeld said Canadian researchers continue to study the best methods of pike control and how they move through the system.
Meantime, British Columbia’s netting catch rates on pike have gone down significantly, as they have on the Pend Oreille.
“We’ve dropped from the thousands to the hundreds a season,” Neufeld said. “But we still catch ripe fish every year.”
Guy Norman, a Washington member of Northwest Power and Conservation Council, joined the Colville Tribe to observe the pike netting operation last week.
“It’s pretty alarming to see what they’re pulling out,” said Norman, who recently retired from the Washington Fish and Wildlife Department, where he had been the regional manager dealing largely with salmon issues.
“I don’t think anyone has a handle on the extent of the problem.
“We’re really concerned about the continuation of pike migration downriver and into anadromous salmon and steelhead productive areas where they could set back recovery of endangered fisheries.
“We already have bass and walleye downstream, but northern pike are notably voracious predators. They’re large and would be an additional predator.”
Controlling invasive species is one of the council’s funding priorities and pike fit the bill, he said.
“We need to get on top of it.”