Pike Close In On Clark Fork

The northern pike invasion that has ravaged one Western Montana trout fishery after another during the past two decades has arrived at Missoula’s doorstep.

Now the Clark Fork River, and its promising native trout recovery, is the next domino teetering in the path of the voracious predators.

And state fish and wildlife officials may not be able to do much about it.

Two weeks ago, Montana Fish, Wildlife and Parks Department (FWP) biologists confirmed their worst fears about northern pike in Milltown Reservoir.

Using gillnets, researchers were able to estimate several thousand pike in the reservoir near Bonner, Mont.

Most of the pike netted were three-year-olds weighing about 3 pounds. Thousands of smaller young-of-the-year were found dead on the rocks as the reservoir was drawn-down for dam repairs.

“They’re fecundity is incredible,” said Brent Mabbott, a Montana Power Co. biologist, who was assisting with the study. “And they grow so stinking fast. That’s how they take over.”

Stomach samples of the pike showed they ate every type of fish available to them, mainly whitefish, and including trout, Mabbott said. Previous studies of the reservoir showed northern pikeminnows (formerly squawfish) as its predominant fish. Pike virtually have replaced them as predators.

The gill-netting survey confirmed the grave suspicions that overcame the FWP biologists’ after they had conducted an electro-fishing survey on a three-mile stretch of the Clark Fork River downstream from Milltown Dam last spring.

In that study, they captured 40 pike that averaged 24 inches. They ranged up to 12 pounds. The population was estimated at 37 pike per river mile, 10 percent of the estimated trout numbers.

“It’s another threat to the trout fishery,” said Ladd Knotek, a Fish, Wildlife and Parks Department biologist in charge of the Clark Fork River fishery. “And I don’t think it could be in a worse place - at the confluence of several major rivers.

“It’s not just a threat for native fish, but for the trout fishery in general, including the browns and rainbows that are the majority of the fishery.

“Now we have a seed source of pike for several river systems. It may not be the best habitat for them, but once they go over the dam, where are they going to go? All the way down the Clark Fork.”

Trout fisheries in the upper Clark Fork, Rock Creek, Bitterroot and the Blackfoot rivers also are in jeopardy from the pike, Knotek said.

“The real travesty,” said state biologist David Schmetterling, “is that we’ve done so much to protect water quality and quantity, restore habitat, and worked with regulations and educating anglers about identifying native trout.

“We’re seeing increases in those species all across the region. Now, all those efforts can be undermined by an illegal pike introduction.”

Biologists believe the pike in Milltown Reservoir came downstream from Salmon Lake, which along with other lakes in the Clearwater chain, was infested with pike after an illegal introduction about 15 years ago.

This spring, word quickly spread among local anglers of the excellent pike fishing suddenly available in the river and reservoir.

“The best thing we can do is to encourage and promote angling for pike, even though I don’t know of any situations where pike populations have been controlled by angling,” Knotek said.

“Some people are mad because we’re gill-netting pike; and others are mad because we’re not killing them all,” he added, noting that some Montana anglers want more opportunity to catch warmwater species.

In the case of the Clark Fork, however, he said, “Pike aren’t the preferred fish in that system.”