Westslope cutthroat trout
Native salmonid of the upper Columbia and Missouri river basins.
The Westslope cutthroat trout is a freshwater fish native to western North America. It serves as the state fish of Montana and faces threats from habitat loss and non-native species. Genetic studies have reclassified it within the Pacific salmon genus.
- State fish of Montana
- Distinctive red mark under jaw
- Pure populations in under 3% of range
- Named after Meriwether Lewis
- Threatened by hybridization with rainbow trout
What it is
This salmonid features small dark spots clustered near the tail and an orange-hued body. A distinctive red, pink, or orange mark sits beneath the jaw, giving the group its common name. Teeth line the roof of the mouth, under the tongue, and at the front. Adults typically measure between 30 and 40 centimetres, though they seldom grow beyond 46 centimetres in length.
Where it lives
Native waters include the upper Columbia system in northern Idaho and British Columbia. Populations exist in northern Snake River tributaries but not the main stem. East of the Continental Divide, they inhabit the upper Missouri, Milk, and North Saskatchewan rivers in Alberta and Montana. Isolated groups remain in Oregon’s John Day River tributaries and Washington’s Cascade Range streams.
How it lives
These opportunistic feeders adjust their diet based on size and habitat availability. Young fish consume macroinvertebrates like caddisflies and mayflies. Larger adults prey on crayfish, molluscs, and other fish. Three life strategies exist: adfluvial forms live in lakes, fluvial types reside in rivers, and stream residents stay in tributaries throughout their lives.
Breeding and life cycle
Spawning behaviour depends on the specific life strategy employed by the population. Adfluvial fish migrate from lakes into tributaries to release eggs. Fluvial individuals move from main rivers to smaller tributary streams for reproduction. Stream resident populations complete their entire reproductive cycle within the same small waterways where they live.
Fish and people
Anglers prize this species for fly fishing, often imitating its natural insect prey. It holds official status as the state fish of Montana. Historical records link its scientific description to the Lewis and Clark Expedition. Specimens collected near Great Falls helped define the taxon, honouring explorer Meriwether Lewis in its scientific naming.
Status and threats
Genetically pure populations occupy less than three percent of their historic range. Habitat destruction from logging, mining, and dams threatens remaining groups. Non-native rainbow and brown trout cause hybridization and competition. Strongholds in Glacier National Park and the Flathead Basin show serious declines due to these combined pressures.
Questions people ask about Westslope cutthroat trout
How can you identify a Westslope cutthroat trout?
Look for small dark freckle-like spots clustered toward the tail and an orange-hued skin tone. The most reliable feature is the red, pink, or orange marking beneath the jaw. They also have teeth on the roof of the mouth and under the tongue.
Where do Westslope cutthroat trout live?
They are native to headwater lakes and streams in the upper Columbia and Missouri river systems. Their range extends across parts of Montana, Idaho, British Columbia, and Alberta. Most remaining pure populations survive in isolated headwater streams above natural barriers.
Why are they considered threatened?
Habitat loss from logging, road building, and dams has reduced their range. Introduced non-native species like rainbow trout compete for resources and hybridize with them. These factors have eliminated the fish from most of its eastern range in Montana.
Good reading and sources
- Westslope cutthroat trout on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Westslope cutthroat trout", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
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