Redeye Bass in the Savannah River system are commonly called Bartram’s Bass. This species of redeye bass has been dealing with some major conservation challenges due to habitat alteration and the introduction of non-native Alabama bass (Micropterus henshalli) into their waters. In the mid-1980s, anglers illegally stocked Alabama bass into Lake Keowee. Prior to the introduction of Alabama bass, the only bass species present were Bartram’s bass and largemouth bass. In less than a decade, Alabama bass became the most frequently caught sportfish (coupled with declining redeye bass populations). In 1997, no genetically pure redeye bass were found. A similar story played out in Lake Russell, another upper Savannah River reservoir, and again Hybridization with non-native bass was to blame for the disappearance of Bartram’s bass, not competition.

Today, all major impoundments in the Savannah River system contain Alabama bass. Migrating fish appear to be hybrids that preferentially mate with pure redeye bass in new waters. This backcrossing creates an overwhelming number of backcrossed individuals, referred to as a hybrid swarm and this phenomenon can be difficult to diagnose phenotypically, requiring genetic monitoring to establish baseline hybridization rates and to determine the extent of hybridization. In 2004, it was determined that the last stronghold of pure Bartram’s Bass populations are in the river and tributary streams. In 2010, 5 of 8 sampled tributaries contained Alabama Bass X Bartram’s Bass hybrids, indicative of upstream migration. There were some encouraging results from a 2021 by Clemson University that 72 out of 93 fish sampled were pure Bartram’s Bass. Continued monitoring of the main river and tributaries will be needed to determine what the long-term effect of hybridization will be in this system.

As if one non-native bass species introduction wasn’t enough, in 2007, anglers illegally stocked smallmouth bass into the Augusta Shoals area of the Savannah River. By 2010, out of 23 fish sampled, 30% were hybrids (Bartram’s X Smallmouth). Since 2013, SCDNR has annually stocked 4,000 Smallmouth bass into Lake Jocassee as part of a sportfish management program and likely exacerbating the hybridization issues already taking place in that system between Bartram’s bass and Alabama bass.

Like the Savannah River system, the Chattahoochee River has also been affected by the introduction of Alabama bass. Lake Lanier was the assumed ground zero for this introduction and Alabama bass have since spread throughout the system threatening native shoal bass and redeye bass populations. GADNR started a large-scale survey of their redeye bass and shoal bass populations in 2018 to determine the extent to which the introduction of Alabama bass have affected their native bass fisheries.

This research revealed that only a few pure populations of Chattahoochee bass persist in a handful of upper Chattahooche River system streams.

Redeye Bass have been introduced outside of their native range in a few different states. Although native to the Conasauga River system (part of the Coosa River) in Tennessee, populations were introduced into the Hiwassee River system in the 1940s and into a few streams of the Cumberland Plateau region in the 1950s. These introductions have had deleterious effects on the native smallmouth bass populations through introgressive hybridization. The hybrids created from redeye bass mating with smallmouth bass are capable of backcrossing with the parental species, over several generations this can erode the genetics of the native species.

In Arizona, a population exists in the Upper Verde River system. These were thought to be introduced in the 1940s by Arizona Game and Fish as “smallmouth bass”. Since this was around the time redeye bass were formally described, it is possible they were mistaken for juvenile smallmouth bass. These introduced populations of redeye bass have impacted many native fishes in this river system, including some species of chub, minnow, and dace that are listed under the U.S. Endangered Species Act. Redeye bass persist in this region and are often caught by anglers eliciting confusion over why the bass are blue!

The towns of Maricao and Jayuya in Puerto Rico have populations of redeye bass from the Chattahoochee River system. These fish were released in the 1960s and persist today.

In the 1950s, California introduced redeye bass from the Coosa River system to establish a sport fishery in waters too cold for other bass, but too warm for trout. These introductions were made to many Sacramento River tributaries that contained smaller, swift-flowing waters. The voracious appetite of predatory redeye bass is implicated in the decline of native ranid frogs and tiger salamanders in these waters. Redeye bass are still caught regularly in California in these areas.

In the last half century, the species of redeye bass in the Mobile River Basin (MRB) have largely flown under the radar. Some people knew about them, and there were a few localized studies in the early 2000s, but as far as large-scale surveys and life history studies go, there were none. This lack of knowledge didn’t sit well with me, especially given the issues going on in the Chattahoochee and Savannah River systems. Although Alabama bass and redeye bass are both native to the MRB, there was evidence of hybridization between the two. We didn’t know how common it is, or why it’s happening, or what factors may be contributing to it.

After many phone calls and e-mails, I moved my family to Auburn where I was set to be the first Presidential Graduate Research Fellow in the School of Fisheries, Allied Aquaculture, and Aquatic Sciences (SFAAS) at Auburn University. This prestigious award provided a substantial stipend with funds contributed by the President’s office, the College of Agriculture, and SFAAS along with a tuition waiver and allowed me to pursue my PhD while studying the redeye bass of the MRB. I hit the ground running and published a paper documenting a population of redeye bass that exist outside of the MRB. I also collaborated with a group in AZ to do the same thing with a population there in the upper Verde River system.

My research also showed substantial hybridization occurring between Alabama bass and redeye bass throughout the Black Warrior and Cahaba River systems, specifically in areas with a lot of habitat disturbance from agricultural pollution and sedimentation from urbanization. Work is ongoing to investigate what specific factors may be facilitating and driving those hybridization events. Not only is hybridization occurring between these two native species, but the rates at which it is occurring is alarming. Those hybridization rates often equal or exceed those observed in the Chattahoochee and Savannah River systems where Alabama bass were introduced. The Coosa and Tallapoosa River systems were in much better shape, but there were specific streams in both of those systems with higher-than-expected levels of hybridization.

As stewards of the waters that we all depend on for life, we actively support and promote all our riverkeepers and the amazing work they do. They are often the first “responders” to issues affecting our water quality and pursuing justice for those responsible. They cannot do this work without the help of monetary donations, and I encourage you to also support them. Their websites where you can learn more about them are linked below.

Another organization dedicated to the conservation, preservation, and restoration of native fish in their native habitat is Native Fish Coalition (NFC). Redeye bass, like many other fish, fall victim to no one advocating on their behalf. Riverkeepers focus on water, but NFC focuses on the fish and the two often work in concert with one another. An all-volunteer national non-profit group, NFC has a chapter in Alabama and all other contiguous southern states containing native redeye bass populations. Each chapter is working on and has completed projects specific to the redeye basses in efforts to increase the public’s understanding and awareness of this native sportfish. The link to learn more about NFC can also be found below.