Whitefish, mountain

(Prosopium williamsoni)

(Girard, 1856); SALMONIDAE FAMILY; also called Rocky Mountain whitefish, Williamson's whitefish, grayling

Endemic to the lakes and streams of the northwestern U.S. and southwestern Canada, from the Lahontan basin in Nevada north to the southern border of the Yukon Territory. It occurs inland into Alberta in Canada and Wyoming in the U.S. Its range overlaps that of the widespread lake whitefish (Coregonus clupeaformis) in British Columbia and Alberta, and slightly overlaps that of the round whitefish (Prosopium cylindraceum) in extreme northern British Columbia near the Yukon border.

Like other salmonids, it has an adipose fin and an axillary process. The mouth, however, is slightly subterminal with the snout extending clearly beyond it. The body is silvery overall. The back is brownish to olive. The scales often have pigmented borders, especially on the back. The ventral and pectoral fins may have an amber hue in adults. The body is nearly cylindrical, but not quite as cylindrical as the body of the round whitefish. It is nevertheless among the species referred to as “round whitefishes”, and is therefore distinguishable from the lake whitefish which has a laterally compressed body.

Though not as important as the lake whitefish, the mountain whitefish has gained some popularity as a sport fish and can be taken by fly fishing or casting with small baits. It provides a considerable winter fishery in places, particularly where steelheads are absent. The flesh is tasty and of good quality

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Current All Tackle Record

5 lbs. 8 ounces.

Similar Species


Whitefish, round