pdf version - South Dakota Department of Game, Fish and Parks

Mountain Sucker
Catostomus platyrhynchus
Quick key characteristics: The mountain sucker is found in cold- and
cool-water habitats. It has small, dull-colored scales and soft fi ns with short
bases. Its downward-facing mouth is wider than long and may exceed head
width, jaws have scraping edges of cartilage inside lips, lower lips are wide,
and there is a distinct notch where the upper and lower lips join. Its blunt,
rounded snout over-hangs the mouth, and its body is tubular in shape.
Similar species in South Dakota: redhorses, other suckers
Identifi cation: The combination of (1) small scales, (2) a notch between upper
and lower lips, and (3) cartilaginous scraping edges on jaws distinguishes the
mountain sucker from similar fi shes in South Dakota.
Range: The mountain sucker is native to the Middle and Northern Rocky
mountains and mountains of the Great Basin and Pacifi c Northwest. It is
restricted to the Black Hills in South Dakota, where it primarily occupies
streams, but may also inhabit impoundments.
Items of interest:
• Feeds on algae and small invertebrates scraped from rocks
• Breeding individuals have an orange or red lateral stripe and tubercles
on lower fi ns (most prominent in males)
• Suitable prey for trout
• Rarely exceeds 6 in
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