Montana Field Guide

The river carpsucker has a widespread distribution in warm-water prairie streams, rivers and reservoirs. Only a few individuals reach the largest weight of about 10 pounds. All suckers have long intestines, which is an adaptation for processing detritus and plant material in addition to the insects, snails and clams they pick up from stream and lake bottoms. The chief value of suckers is as forage and bait for sport fishes. Most fishermen believe that suckers compete with trout, but most species of fish that have evolved together as these have developed mechanisms to minimize competition. River carpsuckers are occasionally caught on hook and line.

Sides silvery, back brown to olive, underside white. Lower fins white.

May make extensive spawning runs to larger tributary streams e.g., Marias River, Tongue River.

Reservoirs and the pools and backwaters of rivers. Spawn in larger streams with backwater areas.

Mostly diatoms and filamentous algae from the stream bottom, but also aquatic invertebrate larvae make up a large portion of the diet..

Downstream portions of Yellowstone River important as rearing areas. A schooling fish.

Spawns May - July over vegetation along shorelines of reservoir and quiet areas of streams. Incubation: 8-15 days. Sexually mature at 2-3 yrs. Spawn peaks in June on middle Missouri River.