Choctaw bass or not?

Mississippi’s newest bass remains a mystery

In 2007, fishery researchers Brandon Barthel, John Knight and Mike Tringali at the Florida Fish and Wildlife Research Institute were conducting genetic analysis of black bass in Florida Panhandle rivers when they found a DNA profile from a Chipola River specimen that didn’t match any other known black bass.

By 2009, the same unusual DNA profile was subsequently found in other Panhandle rivers: Blackwater, Choctawhatchee, Conecuh, Escambia, Perdido and Yellow rivers.

Further sampling suggested this novel fish might also swim in rivers of southwestern Alabama and southeastern Mississippi.

It is now clear that Florida has a new native black bass: the Choctaw bass.

Does Mississippi have a new native black bass, too?

Skipping to the end of this mystery, Mississippi might have a new species of native black bass, but it probably is not the Choctaw bass.

Understanding the distribution of all black bass across the Deep South will help make sense of this “what is it” game. It is also important to realize that the Choctaw bass is not the only “new” species of black bass.

The Florida subspecies of largemouth bass has been elevated to a species, the Florida bass. What was called the northern subspecies of largemouth bass is a separate species and retains the name largemouth bass.

Biologists also now recognize that what was formerly spotted bass, often called Kentucky spotted bass, is actually two species of spotted bass — the spotted bass and the Alabama bass.

The spotted bass and Alabama bass are essentially identical in appearance unless you are an expert ichthyologist or a very patient angler. I’ll fill you in on these fish next month.

The spotted bass live throughout most of Mississippi and the Tennessee River valley. The Alabama bass is confined to the Mobile drainage, which includes the Tombigbee River in northeastern Mississippi.

Let’s put these new species on the map.

Largemouth bass live across the entire Gulf coast. The Florida bass is native to peninsular Florida and probably southern Georgia. This species has been widely stocked outside its native range, so the Florida bass can also be found throughout the Gulf states, where they frequently hybridize with native largemouth bass.

Choctaw bass are confined to eastern Alabama and Florida Panhandle rivers. Alabama bass live in the inverted triangle of the Mobile basin that starts at the Mobile River and expands northward to cover most of Alabama, far eastern Mississippi and northwestern Georgia.

Spotted bass occur throughout Mississippi, except the Pascagoula and possibly the Pearl rivers, Louisiana, western Georgia and eastern Texas.

The Guadalupe bass has a very limited distribution in south-central Texas.

The range of the Choctaw bass is bounded on the north and west by the range of Alabama bass. The range of the yet-to-be-named bass in Mississippi suspected of being a Choctaw bass is bounded on the east by the range of Alabama bass, and to the north and west by the range of spotted bass.

Identifying Choctaw bass

Put simply, Choctaw bass look like spotted bass, which is why they have gone undetected for so many years.

Patient anglers can, with reasonable certainty, separate Choctaw bass from spotted bass by counting fin rays. The dorsal fin (top fin) of black bass has a forward part of hard spines (spiny dorsal fin) separated by a notch from the soft dorsal fin containing flexible fin rays. Choctaw bass have 11 soft dorsal-fin rays, and spotted bass (and other black bass) have 12.

The anal fin (the bottom fin behind the vent) of black bass has several short, hard spines, with the rest of the fin made of longer, flexible fin rays. The Choctaw bass usually has nine anal fin rays, the spotted bass (and other black bass) has 10 anal fin rays.

However, positive identification requires complex genetic analysis.

The bass in Mississippi once suspected to be Choctaw bass look like the Florida Panhandle Choctaw bass, but looks are deceiving. The genetic profiles are different from Choctaw bass, spotted bass and Alabama bass. While the data support Choctaw bass from the Florida Panhandle as a genetically distinct species, the spotted bass-like fish from the Pascagoula River are rather variable — some have genetic traits expected of a spotted bass and others have a mixture of Alabama bass and spotted bass genetic traits.

Additional genetic techniques suggest that these Chotaw bass look-alikes in Mississippi might have a Guadalupe bass ancestor. Analysis of Choctaw-like specimens from the Pearl River is ongoing.

Many details remain to be worked out, and decisions about new bass species — including the yet-to-be-determined bass in the Pascagoula and (possibly) Pearl rivers — will be based on genetic data.

And that leads to a challenging and important management and conservation question: How can we manage a species if we can’t identify it when we collect (or catch) it?