Status, distribution, and resource requirements of the longnose dace Rhinichthys cataractae (Valenciennes) in the Wisconsin Driftless region of Illinois

The longnose dace Rhinichthys cataractae (Valenciennes) is a small, elongated, slightly dorsoventrally compressed minnow that possesses the widest distribution of any North American cyprinid. In Illinois, it is known from streams in the Wisconsin Driftless Area and the shoreline of Lake Michigan. We examined the distribution and population status, habitat requirements, and diet of R. cataractae in the Wisconsin Driftless Area in Illinois. The dace was collected at 11 of the 33 sites sampled, and catch-per-unit-effort (standardized by number of individuals per hour collecting) varied from 0.8 to 52 per site. It was found most often in gravel/cobble riffles in small- to medium-sized streams. Stable isotope analysis showed the diet of R. cataractae to be dominated by macroinvertebrates and periphyton. Although its range is limited in Illinois, the dace is locally abundant in several basins and we feel it does not warrant listing at this time.