Alabama bass invasion

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Steve Sammons, Auburn University

ASHEVILLE, N.C. — A species of bass once mostly confined to a small native range now is spreading far outside that range, occasionally stocked by fishery managers but more often now aided by anglers who either don't understand or care about the negative consequences that illegal introductions can have.

That fish is the Alabama bass, once considered a subspecies of spotted bass but recognized by fisheries experts as a separate species a little more than a decade ago. Yes, it looks like the spotted bass, but it grows larger — in its native waters and in some western reservoirs where all black bass are non-native introductions.

Where it has been illegally introduced, however, it often eliminates smallmouth bass by hybridization and/or outcompetes largemouth bass for forage and habitat, especially in clear, deep reservoirs. Even in stocked reservoirs in Northern California where a heavy trout and Kokanee diet has produced new world records, Alabama bass have reduced or replaced smallmouth and largemouth in many systems that were once known as quality fisheries for these other black bass. Anglers now report catching Alabama bass at a rate of 3 to 1 over smallmouth or largemouth in some reservoirs and rivers.

At present, Ground Zero for this most recent outbreak of illegal introductions is eastern Tennessee and much of North Carolina. The fish are likely being introduced by anglers bringing them in from the species’ native range in the Coosa River system in Alabama, or from northern Georgia waters where Alabama bass have been established for some time.

"We had national-class fisheries rivaled only by Texas and Florida. Now they are ruined," said an angry Bill Frazier, conservation director for the North Carolina B.A.S.S. Nation (NCBN). "It is an outrageous mess that has occurred in about the last five to seven years.” 

"What is most embarrassing about the situation is when the people with the biggest stake in the sport are the ones destroying it. They actually brag about it," he added.

After Alabama bass destroyed smallmouth fisheries in Georgia's Blue Ridge and Chatuge Lakes, "Now we are seeing this happen in North Carolina with the same results," said Steve Sammons, an Auburn fisheries scientist who specializes in black bass species. 

"Alabama bass are an extremely adaptable, aggressive fish that tend to be able to outcompete or hybridize with almost any other bass species they come in contact with," he continued. "We are seeing similar impacts with Shoal bass in the ACF (Apalachicola/Chattahoochee/Flint River system), Bartrams bass (redeye) in the Savannah, and now Tennessee is starting to see this happen in the upper Tennessee River system."

Of special concern are the world-class native smallmouth fisheries in the Volunteer State, such as Norris and Dale Hollow, which are worth millions of dollars to local economics.

"All prior experience shows that if this (illegal introductions) happens, those fisheries would be gone, wiped off the map, never to return," Sammons said. "And it happens fast. If Alabama bass were put in there today, in less than 20 years, those fisheries would disappear."

There was recent genetic confirmation that Alabama bass have been illegally introduced, or made their way by connecting waterways, to TVA’s Wilson and Pickwick Reservoirs where Alabama and smallmouth bass hybrids (often referred to as Meanmouth bass) are being caught in the Wilson tailwater and the upper reaches of Pickwick.

Watts Bar is another fishery that concerns Mark Thurman, a fisheries biologist with the Tennessee Wildlife Resources Agency. Alabama bass already are established there in one embayment and the population is growing.

"The general angling public looks at all fish as being similar," he added. "And it doesn't take a lot of Alabama bass to establish a population and start to hybridize. Once that happens, then you start to see a decline in the quality of the smallmouth fishery like at Parksville, where largemouth bass also were impacted."

Some anglers dismiss the idea that introducing Alabama bass could harm Chickamauga, one of the nation's most popular largemouth fisheries. After all, it's spread across 36,000 acres with lots of vegetation and shallow-water habitat, generally more conducive to largemouth than Alabama bass. But Thurman worries about that fishery too.

"Chickamauga is bigger than Parksville, so it would take longer to see," he said. "But I feel confident in saying that there's the potential for damage, and it doesn't take a whole lot of fish to start the process."

In adjacent North Carolina, meanwhile, illegally introduced Alabama bass all but eliminated largemouth from the main body of Lake Norman.

"There's been no introgression (hybridization) with largemouth bass," said Lawrence Dorsey, a fisheries biologist with the North Carolina Wildlife Resources Commission. "It's been a competition thing."

And while anglers might be impressed by the Alabama bass' growth potential in its native Coosa River system, the North Carolina biologist pointed out that is not likely to be the case in waters where they are illegally introduced, with Norman as a prime example. "We are not seeing anything good come out of this. Take it out of its native range, and you just don't see the growth," he said.

"But we are stuck where we are (at Norman). There are still largemouth there. In a tournament, you catch five Alabama bass, and then try to go find a largemouth to increase your weight."

Meanwhile, Alabama bass now make up an estimated 32 percent of the bass population at Lake Gaston, up from 8 percent in 2016.

North Carolina smallmouth fisheries are suffering too. For example, 75 percent of 50 smallmouth sampled contained Alabama bass genes at Fontana Lake. To the east on the Catawba chain, the hybridization rate was 33 percent at Lake James.

"James seems to be about 10 years behind Fontana," said biologist Scott Loftis. "But the trend points to complete hybridization of smallmouth fisheries."

Loftis pointed out that largemouth, smallmouth and spotted bass "co-existed with no issues" in North Carolina waters. "But with Alabama bass, we're seeing dramatic issues."

According to B.A.S.S. National Conservation Director Gene Gilliland, “Transferring fish from outside a species native range and stocking them in public waters is illegal in almost every state. Yet we see this problem more and more with bass anglers moving fish in hopes it will make their fishing better. But in almost every case, unintended consequences catch up with them, and the results are far worse than what they started with.”

So, what can be done about these issues? Gilliland stresses, “Leave fish stocking to the biologist, to the professionals who understand those systems and species interactions.”

NCBN President Chuck Murray said that B.A.S.S. members must be at the forefront of educating bass anglers about how Alabama bass can harm their fisheries.

Frazier added, "If you see something, say something. Take pictures and include boat or license plates. Help us stop the smugglers."