A full-fledged effort to knock back non-native northern pike populations in eastern Washington’s Box Canyon reservoir on the Pend Oreille River has proved a success so far.
More than 4,552 fish have been removed this spring via a concentrated netting effort in sloughy, side-channel spawning areas that the predatory fish are known to haunt.
The idea is to reduce the northern pike population, and thus reduce their impact on native fish and other game fish -- and lessen the likelihood that they will flood downriver and get footholds in the Columbia River system.
The Pend Oreille flows out of Idaho’s Lake Pend Oreille and into Washington at Newport then north into British Columbia where it empties into the Columbia just above the border.
“It’s relatively confined in the Pend Oreille system and that’s where we want it to stay,” the Washington Department of Fish and Wildlife’s Bill Baker said of the northern pike. “We don’t want those things to get into anadromous waters.”
Pike are very voracious predators that can grow to a relatively large size. Young salmon and steelhead downstream would be likely prey for the northerns.
“They have enough stresses already,” Baker said of salmon and steelhead. A total of 13 Columbia/Snake river stocks are listed under the Endangered Species Act.
It is believed the pike were moved downstream from Montana’s Clark Fork-Flathead system, where they were initially introduced illegally in the 1970s or 1980s. The pike were believed to be flushed down the Clark Fork and into Lake Pend Oreille, which they likely found inhospitable because of its deep, steep nature, and the fact that its pool elevation fluctuates considerably over the course of a year.
The northerns likely then flushed out of Lake Pend Oreille and into the Pend Oreille River during the flooding that resulted in 1997 during the meltdown of one of the biggest snowpacks on record.
In Box Canyon the pike found a place they could call home. It featured shallows and off-channel sloughs, typically at the mouths of tributary creeks, ideal for springtime spawning and rearing. The southern half of the reservoir seems particularly well suited to the pike, Baker said.
The state and the Kalispel Tribe of Indians, who make northeast Washington home, devised a plan to help control the northern pike, which pose a threat to local species including cutthroat trout and Endangered Species Act-listed bull trout.
Northern pike were detected in Box Canyon Reservoir, Pend Oreille River in a 2004 standardized warm water fish survey. And the Kalispel Tribe has documented exponential growth of the population from 400 adults to 5500 adults between 2006-2010, at minimum, and expansion in range within the reservoir.
Northern pike have been documented in Boundary Reservoir and the free flowing Columbia River in Canada, as well as Lake Roosevelt and three lakes in Spokane County.
There have also been several pike reported caught on hook and line in the Columbia River upstream from Kettle Falls. Anglers reported catching pike in the Columbia River during the summer of 2011 just north of the border in British Columbia, near Northport in Washington and near China Bend, just upstream of Kettle Falls, according to WDFW.
Kettle Falls is near the head of Lake Roosevelt, the 150-mile-long reservoir held back by Grand Coulee Dam in central Washington. Should the pike move past Grand Coulee and Chief Joseph Dam, located 51 miles downstream, they would be in salmon territory. Salmon passage to historic habitat is now blocked by the dams, but they inhabit the mainstem below the Chief Joseph down to the river mouth, as well tributaries.
And though northerns have been identified elsewhere, Baker said the Box Canyon pike are the only known self-sustaining population in Washington State.
They have their fans.
“It has drawn quite a few anglers” from the area’s Spokane and Pend Oreille counties and elsewhere, according to the tribe’s Jason Connor.
“It’s a tough position to be in,” he said of the decision to actively suppress the pike population.
The pike’s aggressive feeding “comes at a cost to every other fish species” in the system, Conner said.
“It would be irresponsible for us not to do anything,” he said.
The state over the past year declassified the pike from its “game” fish status and approved a two-pole endorsement, which went into effect May 1, for Box Canyon and Boundary Reservoirs on the Pend Oreille River. The idea is to allow a relatively unfettered harvest of the fish.
The two-pole rule produced “no resistance at all that I met with” from anglers, Baker said. Removing the protections prescribed for game fish “was a little more controversial. The WDFW and tribe held public meetings last year, and this spring in Usk and Spokane, to explain the rationale for the suppression effort, which will include “PikePalooza” fishing derbies June 29-July 1 and Aug. 3-5.
The big bite, however, comes from the tribe’s gill-netting, which began “near ice-off” and was scheduled to continue through April 22, Connor said.
The netting has been focused on “30 locations where we know pike congregate and spawn in the spring,” Conner said. The northern pike netted averaged 24 inches in length and about 3 ½ pounds.
Bycatch with the one-inch mesh nets has included, in vast majority, yellow perch. Also netted were tench, black crappie, brown bullhead and pumpkinseed. All were released with an estimate of less than 10 percent mortality, Connor said.
The tribe contracted with a commercial fertilizer producer to dispose of the pike swept up in the nets.
After April 22 the tribal fishers conducted “Spring Pike Index Netting,” a method developed to evaluate abundance in the reservoir. The result was 2.9 fish per net, down from 13.2 during netting conducted last year.
“That’s pretty encouraging,” Connor said. It did not, however, reduce pike incidence to 1.73 fish per net, the goal of the suppression program, which would represent an 87 percent reduction in the estimated population.
So the netting continues. The tribes this spring have employed from 12-20 nets, each about 150 feet in length. Each net was set one day and checked the next. In all through April 22 the tribe implemented 524 overnight sets. That involved eight people, employing 18-foot skiffs and working alternating shifts that stretched seven days per week.
The tribe plans to implement the spawning season netting for three years, targeting fish that are 2 years old and older.
“We’re looking to crash year classes” of the fish population, Connor said. This year’s fishing will continue into June, though no longer on weekends.
“We don’t think it’s feasible to eradicate them here because the habitat is so well suited to them,” Connor said. But it is hoped the population, and the damage they cause, can be held to a relative minimum.