Robust Redhorse

Illustration by Duane Raver
(Enlarge image)

Scientific Name: Moxostoma robustum

Classification: State Endangered

Abundance: Rare (dark area)

Fact Sheet (pdf)


Robust Redhorse being released into Pee Dee River (Photo by Jodie Owen/NCWRC)

Robust Redhorse closeup (Photo by Todd Pusser)

Female Robust Redhorse collected from Pee Dee River for spawning (Photo by Jodie Owen/NCWRC)

Additional Information

The robust redhorse is a large sucker native to the southern Atlantic slope, both in the Piedmont and Coastal Plain rivers of NC, SC, and GA. This species was “lost to science” for over 120 years after its initial description in the Yadkin River near Winston-Salem, NC. Specimens were finally correctly identified in the 1990s. Today, robust redhorse are found in the lower Pee Dee River in North Carolina, downstream of Blewett Falls Dam. Robust redhorse range map. This population is limited by the presence of dams and impoundments in the river and faces threats in the form of habitat loss and pollutants such as sediment. Additional populations occur in South Carolina (Pee Dee and Savannah Rivers, with stocked populations in the Broad and Wateree Rivers) and Georgia (Oconee, Ocmulgee, Broad, and Ogeechee Rivers, with stocked populations in the Broad and Ogeechee Rivers).

The Robust redhorse is the largest of the redhorse species and can grow up to 30 inches in length. This is a thick-bodied fish with large scales and distinctive fleshy lips. The body is golden brown to coppery or brassy in sheen and the back and sides are usually well contrasted with the light belly.  Its lower fins are reddish orange in coloration and sometimes the caudal fin dorsal fin are a deeper red (especially in young fish). Tubercles are found on the snout, cheeks, underside of head, and anal and caudal fins of the breeding males.

Robust redhorse prefer large rivers with rock and gravel shoals and fast-moving water in which to spawn.  In non-spawning seasons, fish seek refuge in deep, slow water around river bends with large woody debris. Some individuals will remain near spawning shoals year round, while others will travel over 100 river kilometers downstream to the coastal plain. Spawning activity over gravel shoals commences when water temperatures approach 17 degrees Centigrade in the spring (late April/early May).  Robust redhorse reach maturity around 5-6 years of age; the oldest recorded specimen was 27 years old.  It feeds primarily on mollusks, aquatic insects, and crustaceans, crushing its food with its large molar-like teeth. 

Learn more by reading the Robust Redhorse Fact Sheet.

The robust redhorse is protected under the state Endangered Species Act. No robust redhorse can be collected or killed without a permit from the NC Wildlife Resources Commission. 

Robust Redhorse Conservation Plan for North Carolina (~9 MB PDF)
Robust Redhorse Conservation Plan for North Carolina (~1 MD PDF)

Since the formation of the Robust Redhorse Conservation Committee in 1995, NCWRC has worked cooperatively with power companies, aquariums, state and federal resource agencies, and universities to research and conserve this unique species.  Since 2000, over 60 individuals have been captured and tagged in the Pee Dee River, some are outfitted with radio tags that are used to monitor movements throughout the year and document spawning locations. These data have allowed the identification of important spawning shoals within the Pee Dee River, as well as range sizes, wintering areas, and population size estimates.  Additionally, intensive spawning and non-spawning habitat studies have furthered understanding of areas most important to these fish throughout their life cycle. 

Population estimates have  shown that there are currently less than 100 fish breeding in the Pee Dee River as of 2009.  Protection of their spawning areas and other vital habitat will be critical for the survival of this species into the future.