The river carpsucker was originally reported as a discrete species from the plains carpsucker (Carpiodes forbesi), but they are presently considered synonymous. This carpsucker is widely distributed and abundant in Iowa, occurring in large numbers in nearly all of the large interior rivers, as well as in the Mississippi and Missouri rivers. River carpsucker is highly adaptable to variable habitats, but it prefers large, silty rivers with slower-moving current over sand or silt bottoms. It also occurs in the smaller creeks and thrives in river impoundments.

The body of river carpsucker is stout; the back is moderately compressed and slightly arched. River carpsucker has a nipple-like projection at the middle of its lower lip. The back is brown-olive in color with silvery sides fading to a whitish belly. The fins are opaque except in older fish. Breeding males develop minute tubercules about the body. River carpsucker is the largest of the carpsuckers with adults commonly l2 to l8 inches long and weigh l to 3 pounds. Individual fish weighing over l0 pounds have been reported.

River carpsucker congregate into large schools and forage near the bottom. It browses on algae, protozoans, small crustaceans, aquatic insects, aquatic worms and mollusks.

Adults become sexually mature at ages II and III, depending upon sex. This fish spawns late in the spring at water temperature ranges of 65 to 75 degrees F. Spawning occurs in large fish congregations in flowing water over gravel and sandy bottoms. No defined spawning peak occurs as females do not ripen synchronously. Some females might spawn more than once per year. The adhesive eggs are broadcast at random. Fecundity of an average female is over 100,000 eggs. Incubation takes from 8 to l5 days. Average body length at each year of life is: 1-6.8 inches, 2-11.0 inches, 3-14.4 inches, 4-17.3 inches, 5-17.4 inches and 6-l8.0 inches. Fish more than six years old are seldom observed, although river carpsuckers up to l0 years of age have been reported.

*Mayhew, J. (editor). 1987. Iowa Fish and Fishing. Iowa Department of Natural Resources, Des Moines, Iowa. 323 pp.