Fisheries managers on both sides of the border are renewing efforts to control the northern pike population in the Columbia River and keep the invasive species corralled above the Grand Coulee Dam.
Columbia Basin Trust, BC Hydro, and the province’s Ministry of Forests, Lands, and Natural Resource Operations (MFLNRO) joined forces to fund this year’s program and secured the services of Wood Environmental and Mountain Water Research (MWR) to continue with a pike suppression program for the Columbia River, from the Hugh Keenlyside Dam to the US border, and the Canadian section of the Pend d’Oreille Reservoir.
“It is the first time that we’ve been in the Pend d’Oreille and that anyone has sampled other than Dan (Dan Doutaz, a Thompson Rivers University master’s student),” said MWR biologist Jeremy Baxter. “We just wanted to get a general idea of what the abundance was like and where they might be spawning and to try to suppress them prior to spawning as well.”
Gill netting efforts began the first week of May, with two days of sampling in the Seven Mile Reservoir and three days in Waneta. Over the five days, the MWR crew netted a dozen northern pike in the two sections.
“It was a little bit less than I expected, but to tell you the truth, the water was extremely high and it was very turbid, and so there wasn’t a lot of littoral zones,” said Baxter. “But we caught them in all the same spots that Dan had sampled.”
Baxter also tried new areas and says that the largest pre-spawning females were netted at a yet-to-be-opened Buckley’s Campground just off of the beach.
“In the past when Dan was there, there was just no way that he could set there because it’s a pretty active beach … I think that was where we caught the vast majority of our spawners in the Seven Mile Reservoir.”
The largest from the the Pend d’Oreille measured about 80-cm (31.5 inches) and from the Columbia 90 cm (36-inches), but for Baxter the timing was perfect.
“Most of those were all ripe and full of eggs, or males completely ripe and ready to spawn. But none of them had successfully spawned.”
Netting the pike before the spawn is crucial, as large females can lay as many as 100,000 eggs. And unlike previous years, more males were captured than females, another positive sign.
“It’s vital to get the females out of there before they’re able to lay their eggs, so if we can remove every female, hopefully it will suppress the population moving forward.”
MWR and Wood continued suppression efforts in the Columbia and are just wrapping up eight days of net-sets in the Robson Reach area, the Oxbows, and Waldie and Zuckerberg Islands.
Doutaz studied the migration of northern pike on the Columbia River back in 2016 and radio-tagged 15 pike so he could follow their movements. Incredibly, Baxter and his team captured four of the five remaining tagged pike during their most recent efforts. Considering the massive system, it’s a good indication that pike are returning to the same area to spawn, and suppression is working – at least in the Canadian portion of the river.
“They’re not moving around a lot, they’re spawning in the typical location, they’re all ripe, and we’re getting them before spawning. It suggests to us that the numbers are lower and it’s a good sign.”
However, Baxter notes that they did catch smaller pike that appeared to be in their first year, and in their September suppression effort, captured about a dozen juvenile pike in the Oxbows, indicating that recruitment is occurring.
The suppression effort will continue through the summer at various locations using methods such as gill netting and boat shocking.
Pike first appeared in the Columbia in 2009 and suppression efforts has reduced populations in the Castlegar-Trail section from a peak of 133 pike in 2014 to 49 captured in 2016, and even fewer last year.
The best habitat for pike in one of the last free-flowing sections of the Columbia is the slack-water reaches of the river. Yet, a major concern for fisheries managers is if and when the invasive species get into the Arrow Lakes Reservoir, and the threat they pose to the already declining Kokanee and rainbow trout populations.
One needs only to look across the border at a similar habitat in Lake Roosevelt, where the pike population has grown rapidly since its first appearance just eight years ago.
In 2017, Washington tribal and state managers, along with a bounty program, destroyed close to 5,000 pike, and have removed more than 700 in the early stages of 2018.
Pending approval, Washington States Bonneville Power Administration (BPA) is set to fund close to $1 million per year over five years in an effort to check the pike’s expansion in Lake Roosevelt and beyond the Grand Coulee Dam, where it could threaten ESA (Endangered Species Act) listed salmon and steelhead.
For many, unless funding is secured and suppression efforts increase, the situation will get worse.
“Well, I think over time northern pike in Lake Roosevelt will wipe out all the trout,” Chris Donley, the Washington Department of Fish and Wildlife’s Eastern Region fish program manager, told the Spokesman-Review. “That’s how serious a problem it is.”
Despite Donley’s dire prediction, he believes there are ways the fish can be suppressed. But it will take money and decisive action.
According to the Columbia Basins Fish and Wildlife News Bulletin, the proposed five-year budget, including fiscal year 2018, is $4,505,442 with an average annual budget of $901,088. Nearly two-thirds of next year’s funding would come either directly through BPA, or through BPA funds going to the Colville Tribes or through Washington Department of Fish and Wildlife (WDFW).
And not even Canadian Customs can stop the voracious northern pike from returning across the border to the upper Columbia and Arrow Lakes.
“Any time they could come back, because one of Dan’s fish did migrate back again,” added Baxter. “I think the food source is really good for them up here, and they’re a bit larger up here. It wouldn’t take much for them to come back at any time, so continued suppression is probably going to be required.”