Robust redhorse is a predator of invasive Asiatic clams that threaten the natural balance of Georgia rivers.
The University of Georgia’s College of Veterinary Medicine is lending its expertise to the conservation of an endangered fish species once thought to be extinct in Georgia. Rediscovered in 1991, the robust redhorse is the focus of study by the Wildlife Resources Division of the Georgia Department of Natural Resources in tandem with UGA and Georgia Southern University.
The robust redhorse is a freshwater sucker species native to Georgia and the Carolinas. With strong teeth for crushing and grinding, they are known to consume invasive species of Asiatic clams. Members can grow as long as 31 inches and weigh up to 18 pounds, making them easy to spot, if one is looking. First described in scientific literature in 1869, the fish seemingly vanished for more than a century – in part because it was mistaken for similar species – as alterations to river flows changed its migration patterns.
Now that it’s known again, this so-called “mystery fish” is the target of a collaboration among universities, power companies, and state and federal fisheries managers hoping to increase its numbers.
Dr. Stephen Divers of CVM’s Zoological Medicine Service is working with the agency to implant sonic tracking tags in fish captured and released in the Savannah River. Georgia Southern will track the tagged fishes’ movement to establish patterns and learn how the Clarks Hill (J. Strom Thurmond) Reservoir and the New Savannah Bluff Lock and Dam affect their migrations. 
Divers said the fish are captured and safely anesthetized using a water-borne anesthetic. They are measured, weighed, microchipped and sampled for genetic studies. They are also given antibiotics and pain relievers before a 2-3 cm incision is made along the ventral midline where the transmitter is implanted. The body wall and skin are closed using antibiotic-impregnated sutures. After recovery, the fish are released back into the river.
“The total time from initial capture to release is typically 30 to 60 minutes,” Divers said.
River Systems with Robust Redhorse populations.
In Georgia, the fish migrates upriver from the Coastal Plain to the Piedmont to spawn in spring, then moves back downriver in the summer.
According to the DNR, the Savannah River population of robust redhorse is one of the biggest remaining populations. The fish can be collected more regularly there than in other systems in Georgia, and Georgia Southern samples the river several times per week to establish a population estimate. They are also found in the Altamaha system from the coast to the upstream barriers of Juliette Dam on the Ocmulgee River and the Lake Sinclair Dam on the Oconee River.
They were stocked in the Broad River in the late 1990s, where they were known to have existed before the construction of Clarks Hill Reservoir.
You can help
Report sightings of robust redhorse to (706) 557-3233. There are signs at most Georgia DNR public boat ramps that remind fishermen to “Know your target!,” because the robust redhorse is sometimes mistaken for common carp, an invasive species that many people target.
Learn more about the robust redhorse.
