Gravel Chub

Characteristics

The body is light olive-green above with silvery sides and a light blue lateral band. Its most distinctive feature is the presence of scattered "x" or "y-shaped" dark markings on its sides and back. The small, subterminal mouth is horizontal, and a barbel is present at the end of the maxillary. The eye looks large compared to the head. A complete lateral line has 38 to 43 scales. The dorsal and pelvic fin ray counts are 8 in each, while the pectoral fins vary from 13 to 16 rays, and the anal fin has 7 rays. Strongly hooked pharyngeal teeth are arranged on slender arches in a 4-4 formula. A black or dark mottled peritoneum surrounds the stomach cavity, which has a looped gut.

Distribution

Limited to the large interior rivers of central and northeast Iowa. Found almost exclusively in the forested areas of northeast Iowa, including collections taken from the Shellrock, Cedar, Upper Iowa, Wapsipinicon, Volga and Turkey Rivers. Populations of gravel chub have also been found in the Des Moines River in central and north-central Iowa. This once threatened fish species is more abundant and widely distributed in Iowa than previously known.

Foods

Gravel Chubs are bottom feeders, eating plant debris, which they find within the gravel crevices.

State Record

State Records are not documented for non-game species.

Expert Tip

None

Details

Gravel Chubs live in large, deep riffles and raceways of moderate- or large-sized streams with swift current and substrates of sand and pea-sized gravel without clayey silt. If siltation is rapid, the Gravel Chub may be found in shallower waters with stronger current, as long as its preferred substrate exists. Increased erosion and siltation from intensive agricultural practices has caused a decline of the Gravel Chub in parts of its range. It is tolerant of moderate turbidity and avoids rooted aquatic plants and larger varieties of algae and aquatic mosses.  

These chubs are early spring spawners, preferring clean gravel riffles for spawning sites. Adults will reach 3 1/2-inches.

Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.

Sources:

Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.

Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames.

Photo Credit: photo courtesy of Konrad P. Schmidt, copyright Konrad P. Schmidt.