Mountain whitefish
Prosopium
williamsoni
When my family and I fish the South Fork of the Flathead River each year, we always enjoy catching and eating mountain whitefish. The fillets taste great broiled or fried, but most anglers would never consider eating a whitefish, which they consider a “trash fish,” or a nuisance that competes with more desirable trout. Due to such widespread prejudice, this scrappy, abundant member of the trout family is Montana’s most underutilized fish.
Appearance
Like its trout and salmon cousins, the mountain whitefish has a cylindrical
body. It has a gray-bronze back fading to silvery sides, larger scales
than those of trout, and a small mouth overhung by the upper jaw, giving
it a suckerlike appearance. It can easily be distinguished from suckers
and pikeminnows, however, by the presence of an adipose fin on its back
just forward of the tail fin. Meriwether Lewis described the mountain whitefish
as a “bottle-nosed fish” when he saw it in the upper Missouri
drainage in 1805. Mountain whitefish average about 12 inches in Montana,
but anglers regularly catch larger specimens. The state record mountain
whitefish, just over 5 pounds, was caught in the Kootenai River. Similar
species in Montana include pygmy whitefish (a native species) and lake
whitefish (a non-native).
Distribution
You’ll usually find mountain whitefish in larger streams and rivers
where you find trout. The species is common in large coldwater rivers
and major tributaries on both sides of the Continental Divide in all three
major drainages: the Columbia, Missouri, and Saskatchewan (St. Mary). In
North America, the species is found from Alaska south to the headwaters of
the Colorado River.
Reproduction
Whitefish usually reproduce at three years old, spawning at night in
the fall. They do not build nests. The female broadcasts her eggs over
gravel while the male fertilizes them. A mature female contains about 4,000
eggs. Eggs develop over winter and then hatch in March.
Management
Mountain whitefish outnumber trout 10 to one in rivers such as the
Kootenai, Yellowstone, and Flathead. In the Madison River, mountain
whitefish densities reach an incredible 15,000 fish per mile. While conducting
underwater fish surveys in the South and Middle forks of the Flathead,
I’ve seen portions of the stream bottom completely covered with mountain
whitefish. Despite their abundance, whitefish don’t directly compete
with trout because they use different habitats within a stream. Whitefish
feed on aquatic insects on the stream bottom and usually occupy the lower
stretches of a pool. Trout usually feed higher in the water column of a
river and generally occupy the upper ends of pools. Due to the abundance
of mountain whitefish, FWP allows a harvest limit of 100 fish in the western
and central fishing districts. Few anglers take advantage of the opportunity.
Sporting and Eating Quality
Many a trout angler has sighed in disappointment when what seems to
be a big brown or rainbow turns out to be “just” a mountain
whitefish. Yet whitefish put up an admirable fight (which is why
so many anglers think it’s a trout until they actually see the fish).
Mountain whitefish are also excellent table fare when cooked, smoked,
or pickled. Participants in a Montana State University study agreed:
whitefish and trout taken from the Madison River, when cooked, were
equal in texture, aroma, tenderness, and juiciness. For best results, fillet
the whitefish, remove any brown fat and skin, coat with your favorite
breading, and fry in light oil. Or season the boned and skinned fillets
and microwave them for roughly three minutes per side. All in all, the
mountain whitefish is a hard-fighting, delectable member of the trout family,
worthy of much higher consideration than it currently receives.
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