June 6, 2010 in Outdoors

Pike boom in Pend Oreille River

Exponential increase of northern pike documented
By The Spokesman-Review
 
Photo by Jason Connor photo

A single gillnet set by Kalispell Tribe fisheries researchers on the Pend Oreille caught this assortment of northern pike in 2009, indicating the fish were plentiful and spread through a range of age classes. Even higher densities of fish were caught during sampling in May.Photo by Jason Connor
(Full-size photo)(All photos)

Map of this story's location

Pend Oreille pike stats

 From a sampling of 793 northern pike in May on the Box Canyon Reservoir portion of the Pend Oreille River:

Size range: Up to 44 inches and 30 pounds. (Largest spawned-out female recorded was 43 inches long and 19.4 pounds.)

Dominant age class: 70 percent of the female pike and 78 percent of the males were 20-30 inches long, averaging 5 pounds and 4-5 years old.

Pike diet: Most of the river’s fish species were found in the pike bellies, including perch, northern pikeminnows, suckers, peamouth and bass. Proportions are still being evaluated.

Movements: Some adult pike stay in local areas while a telemetry study found others move long distances, as much as 30 miles in two weeks.

Source: Kalispel Tribe Natural Resources Department

Northern pike are populating the Pend Oreille River with the enthusiasm of immigrants lured to a paradise of free land, free love, no taxes and all the food they can consume. Even researchers were amazed by the numbers of the toothy predators they caught last month in a study on the region’s newest boomtown fishery.

“Where we caught three or four fish in a net last year, we were catching six to nine or more,” said Marc Divens, Washington Fish and Wildlife Department warmwater fisheries researcher. “It surprised us a little. It means there’s a whole heck of a lot of pike up there.”

Word soon spread that 755 pike were caught in gillnets during one five-day survey in 55-mile-long Box Canyon Reservoir.

Some anglers reacted by contacting WDFW officials in Olympia while others began circulating online speculation that the state and Kalispel Tribe were waging war on pike, much as Idaho is responding to Lake Pend Oreille’s mackinaw invasion.

“There’s definitely a buzz out there about this fishery,” said Jason Connor, the tribe’s fisheries project manager. “The number seems like a lot of fish, but 755 is really only a drop in the bucket compared to their abundance.

“The main thing is that we got a lot of really useful information for managing this fishery.”

Although the tribe and the WDFW are concerned about the burgeoning pike numbers, they agree the fishery has made a permanent home in the Pend Oreille.

“There’s no stopping them from coming down from Noxon Reservoir and the Clark Fork,” Divens said. “There’s no plan to get rid of them.”

The research will help fish biologists do what they can to manage the pike with other fish species in mind, as well as for a trophy fishery that has the potential to attract anglers from long distances and boost the local economy significantly, Connor said.

“A bass tournament is on the river this weekend,” he said, noting that the tribe invested in a largemouth hatchery in the early 1990s to enhance the river’s bass fishing.

“A northern pike tournament is scheduled for next weekend,” he added, noting that a tournament-quality fishery would have been a pike dream just six years ago.

From May 2-7, state and tribal researchers sited 60 gillnets in nearly 25 river miles from Pioneer Park near Newport downstream to Riverbend, with 15 nets being set each night. Half of the nets were anchored in sloughs and half were in the main river channel.

Commercial fishermen would have set the nets at sites with the potential to catch the most fish. But the research model required the biologists to place the nets randomly in a grid.

The results were enlightening.

“Nets caught pike regardless of whether they were anchored in 30 feet of water out in the main river or near a slough,” Connor said.

“We also were surprised to catch almost equal numbers of fish in the main river as we did in the sloughs, although the water temperature was virtually the same in both places at the time,” Divens added in a separate interview. “More fish might move into the sloughs as the water warms there.”

“Our previous studies indicate some of the fish move into the shallows before heading back out to deeper water later in June,” Connor said, noting the tribe has been studying the pike since 2004. “This is a crazy spring with unusual water conditions.

“But what we have now is a baseline. We know that pike are increasing exponentially; that the biggest component are 4- and 5-year-olds, and that they are abundant from Albeni Falls Dam to Riverbend,” he said.

A follow-up survey that netted 38 pike farther downstream (north) showed that pike had dispersed in significant numbers all the way to Box Canyon Dam, albeit in smaller size and lower densities than between Newport and Riverbend.

“We think those foot-long pike get booted out of the best habitat during spring spawning and they’re looking for a place to hang out,” Connor said.

The research project hasn’t been getting much respect from pike enthusiasts, who have complained that too many fish were killed and numerous adult pike were prevented from spawning.

But Connor and Divens said the research was well-targeted.

“We got good results by relying on the research they’ve been refining for decades in Ontario and Minnesota,” Divens said

Research considerations included:

•Careful choice of net mesh dimensions.

“We caught less fish of all other species combined than we did pike,” Connor said. “Part of that is practical. You can waste a lot of time pulling yellow perch out of a gillnet.”

•Post-spawn timing.

“More than 70 percent of the pike we caught had already spawned,” Connor said.

Researchers get negative feedback from some of the anglers they contact on the river, he said, “but for the most part when we explain what we’re doing and why, they understand that it’s important for us to get this type of information.”

Fishermen are passionate about their preferred species, he said, noting that pike fishermen are enthused while bass fishermen are concerned that the pike are hurting their fishery.

“The tribe is interested in promoting the northern pike fishery, but high densities of pike and trophy size don’t go hand in hand,” Connor said.

The research could evolve into fishing regulations, but John Whalen, WDFW regional fisheries manager, said it’s too soon to say what the management objectives or rules would be.

Northern pike are not native to Washington and the state has set no catch limits for the species.

Tribal researchers are looking into the possible benefits of offering some protection to pike larger than 30-36 inches – perhaps a one-lunker limit – while promoting harvest and eating of pike in the 20- to 30-inch range.

Northwestern Montana biologists are experimenting with slot limits in a few lakes to protect the pike until they get large enough to feed on 12- to 20-inch pike. At that stage the trophy fish will grow even bigger while helping control their own species population.

“Pike have a tendency to eat themselves out of house and home,” said Jim Vashro, Montana Fish, Wildlife and Parks regional fisheries manager in Kalispell. “We have some lakes where the pike have eaten all the other fish and now they’re eating themselves.

“The lakes are full of hammer handles,” he added, describing the abundance of skinny 12- to 18-inch long pike.

Said Connor, “You have to maintain lower densities of pike to get more fish into the 18- to 30-pound trophy range.”

Still to come, the researchers need to correlate reservoir elevation, river flows and water temperatures to those strong 4- and 5-year-old classes of pike to understand what conditions make the fishery tick.

Anglers who catch tagged fish can help the research by calling the phone number on the tag and reporting the information requested. The data help researchers get a bead on fish movement, survival and growth rates.

The stages of research are important, Connor said, because angling interest and pressure is increasing.

“The majority of the anglers coming to the river are fishing for pike,” he said. “That’s a big change in just the past few years, when most anglers were after bass or other fish.”

Last Sunday, Connor saw six boats in Tiger Slough at one time. “And that’s not a very big area,” he said. “At noon, there were nine boat trailers at the Cusick boat launch, and that was a day with intermittent showers and crappy weather.

“What concerns us now isn’t that pike are here, but that people might be illegally moving fish to waters neighboring the Pend Oreille River, as well as the potential for downstream migration in to the Columbia River.”

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