Press Release

Walleye have been found in Lake Lowell and Lake Cascade, F&G asks anglers to report any walleye catches

The fish are nonnative, can be destructive to other fish species, and are allowed in very limited locations in Idaho

On Tuesday, May 24, Idaho Fish and Game received a report that an angler had caught a walleye in Lake Lowell in mid May. The angler said he was fishing for bass on Caldwell Dam when he landed  a 17-inch walleye. It was the first-ever report of walleye at Lake Lowell and coincides with two other reports of walleye in Southwest Idaho.

The angler threw the fish back, but took photos prior to releasing it. After reading a recent press release about another walleye being caught in Lake Cascade, he called Fish and Game to report his unexpected catch and provided photos. Fisheries biologists confirmed it was a walleye.

“We are definitely concerned with this report,” said Art Butts, Regional Fisheries Manager. “Lake Lowell is one of the better largemouth bass fisheries in the state, and it produces some quality bluegill as well. Throughout the West, there are numerous examples of introduced walleye negatively impacting established panfish and largemouth bass fisheries, so this is something we will be monitoring closely.”

Walleye are nonnative in Idaho and are managed in a very limited numbers of waters in the state because walleye can be harmful to other game fish, take over popular fishing waters and lead to a decrease in fish available for anglers.

Anglers are asked to report unexpected walleye catches

Fish and Game asks anglers who catch a walleye (in waters where they are not supposed to exist) to kill, remove and report them to a regional office. Anglers can keep the fillets, but are being asked to save the carcass and bring it to a regional office, or notify department staff and arrange for a pickup.

“We are particularly interested in those carcasses if anglers catch a walleye in Lake Cascade or Lake Lowell,” Butts said. “But because we do not have any established walleye fisheries in the entire Southwest Region – and these fish shouldn’t be present here – we would also like walleye carcasses if anglers happen to catch one in another waterbody.”

Butts added that Lake Lowell feeds into multiple canals, which could potentially provide walleyes passage to other fisheries, including the Snake River or Boise River.

“While we did not see any walleye during our electrofishing surveys earlier in the spring, we will be doing some additional sampling in the next couple weeks to try and get a handle on the potential abundance of walleye in Lake Lowell,” Butts said.

Walleye are unwelcome in Idaho with a few exceptions

Fish and Game provides walleye in a few, carefully selected reservoirs that are in closed systems so the fish can’t migrate into other waters, and where walleye are suitable for those bodies of water. These include: Salmon Falls Creek Reservoir, Oakley Reservoir and Oneida Narrows Reservoir. Among these locations, walleye are valued by some anglers and diversify fishing opportunity in state.

Walleye have migrated from neighboring states through river systems, and they can use canals and other waterways to migrate from one location to another.

In some cases, irresponsible anglers transplant this highly predatory species. It’s illegal for individuals without proper permits to transport and transplant any fish, and Fish and Game law enforcement staff is looking into both instances in the event that walleye were transplanted illegally. They are asking the public for any further information, and rewards are available for information leading to a citation where someone illegally transplanted fish. People can provide information anonymously through the Citizens Against Poaching tipline, or by calling (800) 632-5999.

What’s wrong with walleye?

Walleye aren’t “bad” fish, they’re just not suitable for most Idaho waters. Walleye are nonnative to Idaho and native to the upper Midwest where they rely on a prolific prey base of minnows and other small fish that are not typically found here.

When walleye are introduced (naturally or illegally transplanted), they can wreak havoc on other fish populations and essentially wipe out some game fish.

“Walleye are voracious predators, and they will throw fisheries out of balance by targeting juvenile fish, such as trout or panfish species,” Fish and Game State Fisheries Manager Joe Kozfkay said. “There isn’t the amount prey species available in Idaho like there is in the upper Midwest. A lot of Idaho’s fisheries can’t support walleye along with panfish, trout and other game fish.”

The impact on anglers

Across the West, walleye have been responsible for game fish population declines, and when they get established, it can funnel time, money and resources that could be better spent managing and enhancing other fisheries.

“When we find them, Fish and Game has to divert resources to first monitor the fishery and estimate how many more walleye might be present. That can get expensive real quick,” Kozfkay said. “And if we have to go in there and remove those walleye, it can cost sportsmen a lot of money."

Fish and Game is currently involved in a large-scale project to minimize the effects of walleye in Lake Pend Oreille, where the fish have become established following an illegal introduction just upstream in Montana.

Biologists are trying to keep the walleye population as low as possible to protect the lake’s kokanee population, along with other trout species. Kokanee are not only a valuable and popular sport fishery, they also provide food for the lake’s world-renowned trophy rainbow trout fishery, and other popular game fish.

Allowing walleye populations to go unchecked and prey on kokanee could crash that critical population and undo decades of restoration work Fish and Game staff has done to boost kokanee populations.

“We would much rather spend that time and money doing other things that benefit anglers, but we can’t ignore walleye and the negative effects they could have on our fisheries,” said Andy Dux, Panhandle Region Fishery Manager.

Worst-case scenario is always lurking

Walleye are difficult, if not impossible, to eradicate using gillnets and other control methods, and anglers are unlikely to control a walleye population through regular sport fishing.

Walleye are notoriously elusive and give seasoned anglers a challenge, even where they are stocked and managed as a game fish. When they dominate other game fish populations, many anglers will abandon those waters to find their favorite fish elsewhere, which means fewer anglers enjoy a once-abundant and popular fishery. While that may sound farfetched in Idaho, it’s happened repeatedly in our neighboring states.

“This is not some unrealistic, low-odds, doomsday scenario. We’ve seen it occur in Wyoming, Montana and Washington,” Kozfkay said. “Again, it’s not that walleye are bad fish, just wrong fish in the wrong places where other fish species are better suited and highly valued by anglers.”

Anglers can be the eyes and ears of the agency

In fisheries like Lake Lowell or Lake Cascade where walleye are newly discovered, Fish and Game strongly encourages anglers to keep any walleye they catch regardless of size and report those fish.

“Anglers can really help in situations like these, and be a valuable tool in identifying where walleye might be,” Kozfkay says.

Fish and Game staff may also be able to determine from which body of water a walleye originated and determine whether the fish naturally migrated, or were illegally transported by an irresponsible angler.

2022 Cascade Walleye
Creative Commons Licence
Idaho Department of Fish and Game/Mike Thomas

Angler holds up a walleye caught in Lake Cascade on May 7, 2022. This is the second illegally-stocked walleye confirmed to be caught out of Lake Cascade.