Prosopium williamsoni

Identification Tips:

• Body slender, elongate, nearly cylindrical in cross section.
• Overall coloration silvery, but light or dark brown or olive on back.
• Scales on back, may have darkened borders.
• Head short; eye diameter less than snout length; snout pointed
• Single flap of skin present between nostrils.
• Mouth small and overhung by snout.
• Dorsal fin:11 - 15 soft rays
• Anal fin: 10 - 13 soft rays,

Conservation Status:

British ColumbiaCanadaNatureserve
COSEWICSpecies at Risk Act
Not at Risk (Yellow List)Not AssessedNoneG5, S5

Information Source: BC Conservation Data Centre:

Life History:

• Feeds mainly on aquatic insect larvae and mollusks, but also small fish, and fish eggs
• Fry feed on plankton
• Feed mostly at dusk and after dark.
• Spawns late October to early December
• Mature in 3rd or 4th year and live 7 or 8 years


• Occurs in lakes and medium to large rivers.
• Spawn over gravel in riffles
• Lake populations may migrate into tributary streams to spawn.


British Columbia
• Most fish-accessible medium to large rivers and lakes throughout the Province

• North America: Mackenzie River drainage in Northwest Territory south through western Canada and northwestern USA in the Pacific, to Nevada and Utah,.

Primary Information Source:
McPhail, J.D. 2007. The Freshwater Fishes of British Columbia. University of Alberta Press. Edmonton, Alberta.

Mountain Whitefish juvenile