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Montana Field Guide

Montana Field Guides

White Sucker - Catostomus commersoni

Native Species

Global Rank: G5
State Rank: S5

Agency Status


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General Description
The white sucker is quite adaptable. It has been collected from virtually all types of water in Montana: muddy, clear, warm, cold, running and standing. As the position of the mouth suggests, it feeds on the bottom and eats an omnivorous diet of detritus and insects. The white sucker is distributed throughout Montana's eastern drainage and is present in our northern watershed as well. They are most abundant in the many reservoirs of eastern Montana. In Montana the largest specimens have been about 5 pounds. Large females can produce over 100,000 eggs and suckers can produce large populations in short periods of time. Any type of attempted population control by man is usually a losing proposition. (FWP) See Snyder and Muth (1990) for a guide to the identification of larvae and early juveniles.

Diagnostic Characteristics
Color is dusky olive brown to nearly black above, shading to cream or white below. Dorsal fin has 11 to 13 rays. Scales are medium sized, 60 to 75 in lateral line.

Species Range
Montana Range

All Ranges
(Click legend blocks to view individual ranges)

Western Hemisphere Range


Observations in Montana Natural Heritage Program Database
Number of Observations: 6045

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Often move into tributary streams to spawn. Tongue River study showed migration into Otter Creek.

Extremely varied. Present in both lakes and streams under a wide variety of considerations, but avoids rapid current. Reaches maximum abundance in man-made impoundments. Spawns over gravel or rocky shoals.

Food Habits
Adults feed on bottom organisms such as aquatic invertebrate diatoms, other algae, and debris.

Young provide considerable forage for game species. White sucker x longnose sucker hybrids have been found in several places in Montana.

Reproductive Characteristics
Sexually mature in 3rd or 4th year. Spawns from April into June. Spawners usually move upstream. Eggs hatch in 12-20 days at 50 degrees F. Spawned early April-early May in Tongue River study.

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Citation for data on this website:
White Sucker — Catostomus commersoni.  Montana Field Guide.  .  Retrieved on , from