Prosopium williamsoni
Prosopium williamsoni
(Mountain Whitefish)
Native Transplant
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Prosopium williamsoni (Girard, 1856)

Common name: Mountain Whitefish

Taxonomy: available through www.itis.govITIS logo

Identification: Scott and Crossman (1973); Wydoski and Whitney (1979); Sigler and Sigler (1987); Page and Burr (1991).

Size: 57 cm.

Native Range: Mackenzie River drainage (Arctic basin), Northern Territories, south through western Canada and northwestern United States in Pacific, Hudson Bay, and upper Missouri River basins, to Truckee River drainage, Nevada, and Sevier River drainage, Utah (Page and Burr 1991).

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Native range data for this species provided in part by NatureServe NS logo
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: This species was introduced into the Cache la Poudre drainage (Wiltzius 1985; P. Walker and Behnke, personal communication) and the Roaring Fork River, a tributary to the Colorado River in Colorado, in 1955. From the Roaring Fork River, the Mountain Whitefish spread to the upper Colorado River (Behnke, personal communication). It was also introduced into the Great Lakes Basin in Michigan in 1920 (Emery 1985).

Ecology: As with many western North American salmonids, Mountain Whitefish generally inhabit clear, cool waters (< 20° C) of high elevation streams, rivers, and lakes (Moyle 2002). Spawning occurs during late fall to early winter (October - December) in shallow areas of small tributaries or shoreline areas of lakes, primarily over gravel, rubble, or cobble bottoms (McAffee 1966; Moyle 2002). Mountain Whitefish are demersal feeders, consuming a range of benthic invertebrates, including insect larva, gastropods, and small crustaceans(McAffee; Ellison 1980; Moyle 2002).

Means of Introduction: Stocked for sportfishing in Colorado and as a game and food fish in Michigan.

Status: Established in Colorado. Extirpated in Michigan.

Remarks: Mountain Whitefish were thought to compete with juvenile and adult trout (McAffee 1966), but the diets of the two species are significant different and brook trout consume whitefish fry (Ellison 1980).

References: (click for full references)

Ellison, J.P. 1980. Diets of mountain whitefish, Prosopium williamsoni (Girard), and brook trout, Salvelins fontinalis (Mitchell), in the Little Walker River, Mono County, California. California Fish and Game 66(2):96-104.

Emery, L. 1985. Review of fish introduced into the Great Lakes, 1819-1974. Great Lakes Fishery Commission Technical Report, volume 45.

McAffee, W. R. 1966. Mountain whitefish. 299-303 in A. Calhoun, ed. Inland Fisheries Management. California Department of Fish and Game.

Moyle, P.B. 2002. Inland fishes of California. 2nd edition. University of California Press, Berkeley, CA.

Page, L.M. and B.M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Guide Series, vol. 42. Houghton Mifflin Company, Boston, MA.

Sigler, W.F., and J.W. Sigler. 1987. Fishes of the Great Basin: a natural history. University of Nevada Press, Reno, NV.

Scott, W.B., and E.J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. Ottawa.

Wiltzius, W.J. 1985. Fish culture and stocking in Colorado, 1872-1978. Division Report 12. Colorado Division of Wildlife.

Wydoski, R.S., and R.R. Whitney. 1979. Inland fishes of Washington. University of Washington Press, Seattle, WA.

Other Resources:
FishBase Fact Sheet

Author: Pam Fuller, and Matt Neilson

Revision Date: 4/10/2012

Citation Information:
Pam Fuller, and Matt Neilson, 2017, Prosopium williamsoni (Girard, 1856): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL,, Revision Date: 4/10/2012, Access Date: 11/21/2017

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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Citation information: U.S. Geological Survey. [2017]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [11/21/2017].

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