Historically, the state-threatened greater redhorse (Moxosyoma valenciennesi) were reported in the Waupaca River system as far upstream as Cary Pond on the Crystal River in the city of Waupaca.  In 1971, a carp (Cyprinus carpio) eradication project on the Waupaca River system was believed to have eliminated greater redhorse from the Waupaca River above the Weyauwega Dam.  In 2005, Qualitative observations during the spring spawning period and mid summer quantitative fish surveys using electrofishing gear were conducted on the Crystal and Waupaca Rivers to determine the status of greater redhorse.  Biologists captured 12 adult greater redhorse and one juvenile and observed 235 additional adult fish on 49.3 km of river during the spring spawning period.  Adult greater redhorse were observed in all four reaches between dams on the Crystal River and two reaches on the Waupaca River.  Spawning areas were limited to two primary sites and one secondary site on the Crystal River and one primary site on the Waupaca River.  Summer electrofishing on 13.9 km of river across 6 sites captured 10 adult greater redhorse and observed six others.  CPE of greater redhorse ranged from 0.0 to 2.9 fish/km.  No young-of-year or juvenile greater redhorse were captured during summer electrofishing.  Additional information needs to be collected on annual recruitment to the population and early life history and habitat use of juvenile greater redhorse.