A slender silvery cousin of lake whitefish, beloved by Western anglers. Often overlooked as "rough fish" but actually a native essential to mountain trout streams.

Also called: Mountain Whitey, Rocky Mountain Whitefish

Native status: Native to western North America

§ Quick facts

SizeLength 25–55 cm typical; record 70 cm
Weight250 g – 2.7 kg; record 2.6 kg
LifespanWild 7–18 years
OrderSalmoniformes
FamilySalmonidae

§ Encyclopedia

The mountain whitefish is one of the most widely distributed salmonid fish of western North America. It is found from the Mackenzie River drainage in Northwest Territories, Canada through western Canada and the northwestern USA in the Pacific, Hudson Bay and upper Missouri River basins to the Truckee River drainage in Nevada and Sevier River drainage in Utah.

Source: Wikipedia — Mountain whitefish Licensed under CC BY-SA 4.0

§ Identification

Field marks. Slender silvery fish with small head, small mouth, deeply forked tail, adipose fin (salmonid character). Distinguished from Round Whitefish by terminal vs. subterminal mouth.

Similar species. Round Whitefish (subterminal mouth; cylindrical body). Lake Whitefish (different range; larger). Various trout (different markings, body shape).

Voice. Silent.

§ Diet & behavior

Diet. Aquatic insects (caddisflies, mayflies, midges, stoneflies) — important link between insect production and predator fish in mountain streams.

Behavior. Common but underappreciated salmonid of western US and Canadian mountain streams. Often overlooked by trout anglers but actually outnumbers trout in most western rivers. Spawns over rocky shoals in late fall (water 4–10°C) without redd construction (unlike trout). Tolerates a wider temperature range than most trout — important indicator species for cold-water stream health as climate warms.

§ Range

Western North America in cold streams

§ Habitat

Cold mountain streams and rivers

§ Threats

Stream sedimentation, climate-driven warming, dam impacts.

§ Conservation status

According to the IUCN Red List, the mountain whitefish is currently classified as Least Concern.

§ What helps

Maintain native mountain whitefish populations. Don't demonize "rough fish." Practice catch-and-release.

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§ Further reading

§ Sources cited

  • American Fisheries Society
  • Idaho Department of Fish and Game
  • Trout Unlimited
  • IUCN Red List 2014