In North Carolina, Lake Norman was ground zero for the invasive Alabama bass — a growing problem that threatens the state's native bass and ecosystems that depend on them.
“The problem really began a little over 20 years ago,” said Lawrence Dorsey, regional fisheries supervisor for the N.C. Wildlife Resources Commission. Duke Energy found the fish during a routine survey the utility conducts to comply with its permit for the McGuire Nuclear Station. “This fish moved downstream into Mountain Island and ultimately into Lake Wylie.”
Alabama bass have since spread across the entire state. Officials hope to measure and control the spread but acknowledge it's an uphill battle. To reduce the population, state regulators have lifted size and creel limits on Alabama and spotted bass.
Alabama bass is invasive because it outcompetes its smallmouth and largemouth cousins — a lose-lose for anglers and the ecosystem.
“Just from a pure angling perspective, the maximum size of an Alabama bass is never going to be as large as the maximum size for a largemouth bass or even a smallmouth bass,” Dorsey said.
The interlopers are smaller than North Carolina's native species and may not perform the same ecological functions that support other aquatic animals, such as freshwater mussels.
“We have a lot of freshwater mussel populations in those rivers and streams that rely on specific fish hosts,” Dorsey said. Similar to how a flower may rely on a specific species of butterfly to pollinate it, mussels have a preference for different bass species to transport their larvae and continue their lifecycle. "Smallmouth bass are native to those rivers and streams, and they perform an ecological function in those streams.”
However, hybridization may endanger that relationship. It occurs when the invasive bass fertilize the native fish’s eggs — a phenomenon that happens more frequently as Alabama bass populations grow. Over time, this hybridization can lead to Alabama bass completely replacing the smallmouth bass.
The bass can travel through free-flowing waters, but Dorsey said people are likely responsible for introducing it to new river basins.
“Some of these are probably folks that have good intentions that have done this,” Dorsey said. “You create long-lasting and, in this case, likely permanent changes to the fisheries.”
It may be too late to put Pandora back in the box, but Dorsey said he hopes the Alabama bass will serve as a cautionary tale for other anglers looking to take matters into their own hands. It’s also illegal to stock fish without a permit.
