Here’s an experience many trout anglers can relate with: You’re fishing a nice stretch of river with a finesse presentation—a nymph, a salmon egg, or a small Panther Martin spinner—when boom! Fish on!
But as the fight unfolds, this fish feels different. After a series of tight head shakes and rolls, you net your catch and discover it’s not a trout, but one of its salmonid cousins—the mountain whitefish.
Whitefish are found across much of Idaho, and they are common bycatch for trout anglers. Locally, they live in the Boise River (including its more remote South, Middle and North Forks), the Payette River, and a handful of smaller tributaries.
One common misconception is that whitefish are undesirable “trash fish.” But they are part of the trout family, and they are viewed as sport fish by Idaho Fish & Game. Whitefish are considered good eating (especially in the smoker), but even if you don’t harvest them, catching one is a good sign—they are a keystone species in river systems, and their presence indicates a healthy environment.
Whitefish are predators, but they have very small mouths, so they primarily eat small insects and aquatic larvae. Big ones will also take snails, other small invertebrates and, occasionally, minnows. An average sized whitefish in our region is 10-to-14 inches. Anything over 16 inches is a very nice fish, and a whitefish over 20 inches is a trophy.
While most anglers catch whitefish by accident, you can target them by drift fishing with ultralight tackle. Tiny midge, egg and bead head nymph patterns are the best lures for tempting a whitefish. Drifting a micro jig, a salmon egg, or a small piece or worm along the bottom will also do the trick. Whitefish lack the acrobatics of a big rainbow or brown trout, but they are scrappy fighters. And if you find one, others are usually nearby—especially in the fall, when they form massive schools for their spawning run.
So, next time you catch a whitefish, don’t be bummed! Catching one means your favorite trout stream is in good shape—and it’s another Idaho species you can cross off your bingo card. Tight lines!