Gravel Chub (Erimystax x-punctatus)

Status: State Endangered (1979).

Occurrence: The lower Rock River drainage, including lower Pecatonica River, lower Sugar River, the main channel of Rock River and lower Turtle Creek. A map outlining Pre-1977 and 1997 to Present Distribution is available.

Aid to ID: Olive green dorsally, silvery on sides, silvery and white on belly. Large "bug" eyes. Scattered "X"-shaped markings on back and sides. Adult length: 3 inches (76 mm).

Habitat: Deep, swift waters of medium-to-large-sized rivers over pea-gravel bottom. Avoid rooted aquatic plants and larger species of algae and aquatic mosses.

Food Habits: Probe under rocks and crevices for desmids, diatoms, plant debris and other vegetation.

Natural History: Gravel chubs spawn in early spring in swift gravel raceways or channels.

Management Considerations: The main reason for the gravel chub's decline is a general lack of its highly specialized habitat and increasing turbidity and siltation of existing sites resulting from agricultural run off. Specific microhabitat requirements may be beneath rocks in riffle areas where the effects of swift water are reduced, but where the current sweeps the gravel bottom clean of silt.

Information compiled from publication ER-091.