Robust Redhorse, Moxostoma robustum
The Mystery Fish
The robust redhorse, Moxostoma robustum, was believed to be extinct for 122 years. This species was first described by Edward Drinker Cope in 1869 and yet the fish remained unknown to scientists until 1991. Georgia Department of Natural Resources biologists discovered several robust redhorse in the Oconee River near Toomsboro, Georgia in August 1991. Scientists estimated that this remnant population, surviving along a 70-mile stretch of river, numbered as few as 2,000. Since the rediscovery, the U.S. Fish and Wildlife Service have joined forces with Georgia DNR and Georgia Power Company to learn about the species and begin efforts towards the prelisted recovery of the robust redhorse. In 1995, the prelisted recovery effort became formalized with a Memorandum of Understanding (MOU) establishing the Robust Redhorse Conservation Committee (RRCC).
Robust redhorse are sizable fish that when fully-grown measure up to 30 inches in length and 17 pounds in weight. The fish has a thick, robust body with rose-colored fins and a fleshy lower lip. The species is a large, long-lived member of the redhorse sucker family. The maximum known age is 27 years. Adult robust redhorse feed on bivalves, including the Asiatic clam (Corbicula), and use molariform pharyngeal teeth to crush shells.
Historically, the robust redhorse was abundant in large Atlantic Slope rivers from the Altamaha River in Georgia to the Pee Dee River in North Carolina. Wild populations are now known to exist in the Ocmulgee and Oconee rivers (Georgia), the Savannah River (Georgia/South Carolina), and the Pee Dee River (North Carolina). Small stocked populations have been established by introducing robust redhorse in the Ocmulgee, Broad, and Ogeechee rivers in Georgia.
Much has been learned about the robust redhorse since its discovery in 1991. However, many questions remain with regards to habitat, life history, and survival threats. The robust redhorse is difficult to sample and may be overlooked or misidentified as a closely-related and more common sucker fish.
The Warm Springs Regional Fisheries Center has been active in the prelisted recovery effort for the robust redhorse. The Warm Springs National Fish Hatchery is the U.S. Fish and Wildlife Service’s lead contact concerning the species and represents the USFWS Fisheries program on the various committees of the RRCC including the Technical Advisory Group, which is the working committee involved with the day-to-day activities of the prelisted recovery effort. The Warm Springs NFH also serves as one of two incubation facilities for eggs used in the re-establishment of robust redhorse populations.
For more information about the robust redhorse program, please contact Carlos Echevarria at 706-655-3382 ext. 1224 or firstname.lastname@example.org.