Flathead catfish discovered in the Ogeechee River

There’s a new alpha-predator in the Ogeechee River, one that can outgrow nearly every native species of fish and will eat just about anything that will fit in its wide, flat mouth.  

Flathead catfish, also known as yellow cats, have invaded almost every river in Georgia, except for the St. Marys, but had not been seen in the Ogeechee until December 2021 when a commercial fisherman caught one in a hoop net.  

The Georgia Department of Natural Resources, which conducts regular annual sampling of fish in all of the state’s rivers, increased its sampling in the Ogeechee after that report. In August of this year they caught the first flathead in their gear.  

“So far this year we’ve caught 20,” said Joel Fleming, a biologist with the Georgia DNR fisheries. “Everything is within 10 miles of I-95. We’re sampling above and below that to make sure they’re not outside of that area.” 

Fleming and his crew use electronic fishing equipment dialed in to target and stun particular types of fish in an area. The fish that are brought to the surface are then surveyed and any invasive species, like flatheads, are removed. 

Fleming said that they will continue shocking the area every few weeks with the hopes of keeping the population at that location under control as much as possible.  

The flatheads they have removed from the Ogeechee so far have ranged from about one pound to a recent catch that was a little over 25-and-a-half pounds.  

A popular gamefish in other river systems, according to DNR’s 2023 sport fishing regulations, the largest flatheads caught on a rod and reel tied at 83 pounds. Both were caught in the Altamaha River, one in 2006 and the other in 2010. Larger flatheads have been caught on limb lines, including one on the Ocmulgee River that weighed 103 pounds. 

Damage to the ecosystem 

The Ogeechee, one of the state’s only free-flowing black water rivers, is known for its panfish, especially its redbreast sunfish, fishery.  

Fisherman from all over the state visit the Ogeechee and Satilla rivers every year to fish for this species Ogeechee Riverkeeper Damon Mullis said. The main threat the flatheads pose is to species popular with recreational fishermen. 

“These fish are going to target red breast pan fish, which is the most popular game fish in the Ogeechee,” Mullis said. “There will certainly be an impact on that population.” 

They also pose a threat to other native species, particularly bullhead catfish, which are much smaller and typically fill a different ecological niche than their foreign counterparts. 

“Bullhead are fairly small catfish,” Mullis said. “The native catfish we have are mostly scavengers or they eat muscles and crayfish and that sort of thing. But the flatheads are top carnivores. They eat other fish. Channel cats will eat other fish, but that’s not their primary diet. Once a flathead gets up to a few pounds, it becomes pretty strictly a predator. They will be one of the top predators in our river. That is the concern. They get so big and dominant and a big fish needs lots of food.” 

Fleming said that it is hard to say how much of an impact any non-native species will have once it is in a new environment or how prolific they will be. But based on what he has seen in other river systems, Fleming said that even with concentrated efforts to control them, he expects them to likely spread up and down the Ogeechee.  

“Over the next 10 years we will see quite a few impacts,” he said. “They’re going to impact our native catfish, and even though bullheads are not premiere game fish, they occupy a different niche in that ecosystem and they’re certainly important.” 

In other river systems, like the Altmaha, populations of native catfish have been devastated to the point that they are rarely seen anymore.  

“Flatheads are an apex predator and they’re going to eat anything around that is smaller,” Fleming said. 

And at the sizes to which they grow, that’s just about every other native fish. 

“Redbreasts do persist,” Fleming added. “I think the fishery will be OK, but it won’t be as robust as it has been in the past."  

How these species spread 

Flatheads originated in rivers on the western part of the state, rivers that drain into the Gulf of Mexico. All of the flatheads that are currently found in rivers that drain into the Atlantic Ocean are considered to be invasive species in Georgia.  

They were were first seen in the Savannah River in 2010 and since then, Fleming said the population has exploded.  

"Originally they were brought over here to these river systems in some form or fashion,” Fleming said. “They must have come over with the illegal stockings here and there and that’s how they got over on the east coast side.” 

He believes the flatheads in the Savannah probably migrated south from Clarks Hill Lake, now known as Lake Thurman, but admits there is no way to know how they first got into the river system.  

“It’s teeming with them now,” he said. “Based on the numbers, we just assumed it was a matter of time before they came over (to the Ogeechee) from the Savannah.” 

Looking at the hydrograph of the Savannah River over the last couple of years, Fleming said that there have clearly been significant summer rains. When all that freshwater rushes downstream it pushes back the more brackish water near the coast, where the Ogeechee joins the Savannah on the way to the ocean. He believes the freshwater from the rains allowed fish from the Savannah to follow food into the smaller river. 

“We don’t know for sure,” Fleming said. “They could have easily been spread by somebody, but based on what we’re seeing, they probably swam upriver. Unfortunately, if it happens once it’s likely to continue to happen. And now there will be natural reproduction in the Ogeechee, I’m sure.” 

For now, DNR plans to continue shocking heavily in the areas where they had been finding flatheads, monitoring the population there, and removing any they find.  

Mullis and Fleming said that they cannot expect to eradicate them. 

“There’s no way to shock every nook and cranny of that system,” Fleming said. “We’re never going to get them all. Anything we do is simply a suppression effort at this point.” 

Both DNR and the Riverkeeper ask that if and when anglers throughout the Ogeechee basin encounter a flathead, they take it out, harvest it, take a photograph and contact DNR with information on where it was caught. This will help them monitor how far and how quickly they spread.  

“Please don’t spread these, or any other invasive species, around,” Fleming said. “If you have fish in your aquarium, please don’t dump them. Dispose of them properly. Don’t put fish where they’re not supposed to be or move fish from drainage to drainage. You never know what you’re going to impact. We hate to see this happen to any of our river systems.”