Angler assistance is critical to managing invasive walleye in salmon and steelhead waters

Salmon and steelhead are valuable resources to Idaho that already face many challenges, and they don’t need more, particularly from illegally introduced walleye that have been creeping up the Snake River. Walleye are voracious, predatory fish that can consume young salmon and steelhead that are rearing, or migrating, in Idaho rivers. Knowing how many walleye are out there is challenging without anglers reporting any walleye they catch (and keep). 

Anyone who catches a walleye in an Idaho river is asked to kill it, take a photo and contact Idaho Fish and Game Biologist Marika Dobos at the Lewiston Regional Office by email at marika.dobos@idfg.idaho.gov, or by calling 208-750-4228.

Information provided by anglers — along with a fish trap at Lower Granite Dam — indicate that walleye are moving upstream of Lower Granite in increasing numbers. The Snake River is immense and long sections of it are difficult to access and monitor fish populations, so trying to understand what is going on with walleye is challenging. Anglers have been key to helping biologists understand walleye distribution in these areas. 

“Anglers have been great about keeping us informed about walleye they’re encountering, and we greatly appreciate that,” Dobos said. “We know it can be an inconvenience to their fishing trips, but catching, keeping and reporting walleye is the best tool biologists have to monitor where these fish are migrating, estimating how many might be out there, and also removing some of them.” 

Until recently, Fish and Game have had only a handful of reported walleye caught in Idaho’s salmon and steelhead rivers, and only four were confirmed with pictures (one in 2020, one in 2019 and three in 2022). Northern pikeminnow can be misidentified as walleye, so Fish and Game asks anglers to provide pictures to confirm the species.

After publishing an article last year asking anglers to report on walleye caught in anadromous waters, Walleye are spreading into Idaho, Fish and Game received and compiled reports from 16 anglers that they caught a total of 18 walleye in 2023, and a few confirmed reports have come in this year. 

"The number of walleye came as a big surprise because so few were reported in the past, and although they were showing up at Lower Granite Dam, we weren’t sure how many, or how successful they were in getting past the dam and into Idaho,” Dobos said. “And we would not have that information if it wasn’t for anglers.” 

Based on the information anglers provided, walleye can now be found in the Snake River all the way up to Hells Canyon Dam, and in the lower Salmon River as far upstream as Riggins. 

These areas are important rearing habitat and migration corridors for hatchery and wild salmon and steelhead. An established population of walleye in these areas and increased expansion into more critical rearing habitat pose a high predation risk for juvenile salmon and steelhead.

Currently, Fish and Game is collaborating with other state, federal and tribal entities to discuss strategies on reducing this risk, however, there are many challenges with walleye in these large river systems. A special thanks goes out to the anglers that have provided us with catch information in Idaho. 

Fish and Game encourages anglers to report walleye catch with location, size and method so information can continue to be used to better understand walleye distribution and aid in targeting harvest effort.

Fish and Game fisheries managers are asking anglers to keep an eye out for walleye outside the three reservoirs the department manages for them, which are Onieda, Oakley and Salmon Falls Creek reservoirs. 

Idaho and walleye just aren’t a good match in most places. Walleye are native to large Midwestern lakes that  have large and prolific forage bases of minnows, shiners, chubs and other small baitfish. Those baitfish are not available in most Idaho waters, so walleye are likely to eat other game fish that are highly valued by Idaho anglers. 

— Idaho Department of Fish and Game