Colorado Fish Species: River Carpsucker

A deep-bodied sucker with a long, falcate (sickle-shaped) dorsal fin; snout short and rounded; mouth short, wide and wholly inferior (on the ventral side of the head); lower lip with a nipple-like projection in the middle. There are 23-27 rays in the dorsal fins; scales are large. The adults are a slate or olivaceous silvery color. Fins are colorless or pinkish yellow. Length at the end of the first year up to 6 inches. Adults in Colorado reach 18-19 inches in length. The average weight of an adult is in excess of 2 pounds ranging to a maximum of 5 1/2 pounds.

 In Colorado, the species is restricted to the lower South Platte River on the eastern plains. Adults are common in Jackson, Jumbo and North Sterling reservoirs. Carpsuckers of all ages, from young to adult, are found in Prewitt Reservoir. Immature fish, 2.5 to 6 inches, are infrequently found in the South Platte mainstem from Fort Morgan downstream to the Nebraska state line (Propst 1982).

In reservoirs, adult carpsuckers are widely distributed through the entire water body and are not restricted to one habitat type. Immature carpsuckers collected in the South Platte are found in quiet backwaters and sloughs over a mud bottom. One reason adult river carpsuckers are found only in reservoirs in Colorado may be that the extremely low flows during fall months leave very few large pools or backwaters required by river dwelling mature fish of this species.

Courtesy of Natural Diversity Informations Source, Colorado Division of Wildlife