A non-native fish is spreading in Idaho, threatening salmon and steelhead, IDFG says

Nicole Blanchard
·2 min read
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Idaho Fish and Game has received more reports this year of a non-native fish species in the Snake and Salmon rivers, prompting the agency to raise the alarm about potential impacts on struggling salmon and steelhead.

In a news release, Fish and Game officials said they’ve received numerous reports of walleye, a predatory fish from the Midwest, on the Snake River near Hells Canyon and on the Salmon River. The agency called the reports “alarming” and said signs point to more walleye on the way to Idaho.

Because walleye are such voracious predators, they pose a risk to salmon and steelhead in Idaho’s waterways.

“Walleye are opportunistic, apex predators that will eat any fish it can get its teeth into,” Fish and Game officials said in the news release.

The agency asked anglers who reel in walleye to keep their catches and “enjoy a very tasty dinner” instead of releasing the fish back into the water. It’s likely to be a popular request — walleye have a reputation as an especially delicious catch.

More walleye found in Idaho

Though they aren’t native to Idaho, walleye aren’t unheard of here. Fish and Game stocks the popular game fish in a few select, isolated reservoirs where the fish aren’t able to spread to other waterways.

But walleye have made their way into other bodies of water regardless.

Decades ago, they were illegally introduced to a Washington lake and spread into the Columbia and Snake River systems. Walleye on the Snake have largely been confined to the lower part of the river in Washington but in recent years have become a common sight at the Lower Granite Dam about 45 miles northwest of Lewiston.

A fish trap captures some walleye before they can migrate past the dam, but many are able to use the dam’s fish ladder to make their way into the upper Snake River — and into Idaho.

Walleye also appear to have been illegally introduced to some Idaho waterways in the last several years. In 2018, a walleye was caught in Lake Cascade, prompting concerns about the species’ impact on perch and bass populations. No other walleye were reported at the lake until last year, when a Fish and Game employee caught one.

Fish and Game asked anyone who catches walleye on Idaho rivers to keep the fish (there is no bag or size limit on walleye) and call the Lewiston Regional Office at 208-799-5010 to report the walleye’s size and approximate location where it was caught.