Big Changes for the Smallmouth Bass

Smallmouth bass are a popular sport fish for many fly anglers, especially those who enjoy fishing in rivers and streams. Reverence for smallmouth bass can even be found in American literature as far back as the 19th Century. In a book titled, Book of the Black Bass, Comprising its Complete Scientific and Life History (published in 1889), author, James A. Henshall states, “Inch for inch and pound for pound, the gamest fish that swims.”

Smallmouth were at the forefront of our minds as our little party of three drove north towards southeastern Oklahoma. The plan was for Travis and I to hit the river in my two-man canoe, while Nick paddled his sit-on-top kayak. We were all looking forward to a weekend of seclusion, adventure, and comradery.

If our goal had merely been to hook into a “smallie” or two, then we could have made the short drive to the Texas Hill Country to find them, but we had a larger mission. We wanted to catch these hard-hitting fish in their native range, where they have always existed, in the streams and rivers surrounded by the wooded hills of eastern Oklahoma. Unbeknownst to us, this trip was going to offer something that no one was expecting, a new species to add to our catch-lists.

As we crossed the Oklahoma-Texas border, it never occurred to us that the “smallmouth” we’d be catching weren’t the black bass species (Micropterus dolomieu) that we thought. A scientific paper (published in June of this year) was ready to hit the press, and possibly upend the historical assumptions of what types of black bass swim in the waters of the United States, including the Ouachita and Ozark Mountain ranges of eastern Oklahoma and western Arkansas.

This paper, titled “Phylogenomics and species delimitation of the economically important Black Basses (Micropterus)” looked at the genetics of different black bass populations throughout the United States. Some of the findings in the paper are quite surprising.

For one, the authors Daemin Kim, Andrew T. Taylor, and Thomas J. Near, claim that largemouth bass should be separated into two distinct groups. The Florida largemouth bass remains part of the species Micropterus salmoides, whereas the populations of largemouth bass west of Alabama, Florida, Georgia, South Carolina, and North Carolina are now delineated as a separate species which the authors call Micropterus nigricans.

Another interesting conclusion found in the paper, and one that changed our assumptions as to what species of bass we were landing in southeastern Oklahoma, was the genetic variation among the populations of smallmouth bass. According to the phylogenomic analysis conducted by the Kim, Taylor, and Near, the smallmouth bass complex has four distinct lineages. The northern variety of smallmouth (Micropterus dolomieu) is the kind people usually think of. However, Kim and colleagues attest the genetic makeup of the “smallies” along the Oklahoma-Arkansas border are different than the northern type.

Debates about whether to recognize and differentiate the southern populations of smallmouth bass is nothing new. Discussions have been ongoing since at least the 1940s. Ichthyologists Carl Hubbs and Reeve Bailey hypothesized that the native “smallmouth” that swam in the Arkansas River system and Neosho River (along the borders of Arkansas, Missouri, and Oklahoma) were morphologically different than the northern populations of smallmouth (Micropterus dolomieu). Hubbs and Bailey pointed to the differences in the size and shape of the fish’s head in order to make their assertion that the native smallmouth of the Neosho River was a separate subspecies called the Neosho Bass (M. dolomieu velox). Since Hubbs and Bailey’s original hypothesis, there has been much discussion about whether to split or lump the Neosho Bass with the broader species of smallmouth. However, judging by this recent paper, not only does Kim, Taylor, and Near suggest the Neosho Bass is indeed a distinct lineage, but the authors also claim that two more southern watersheds contain distinct lineages of smallmouth bass.

These lineages are referred to as the Ouachita Bass (found in the Oauchita River system) and the Little River Bass (found in the Little River system). The latter fish is the variety that we were catching on our trip to southeastern Oklahoma. Both of these lineages are still yet undescribed in terms of their morphological differences, but according to the authors, the genetic variation is distinct enough to be considered their own subspecies (or perhaps elevated to the species rank on the taxonomic scale).

You may be reading this and say to yourself, “So what, does any of this really matter? Why do we even bother with the nuanced distinctions between these subspecies?”

I understand this sentiment, especially because all of these variations of black bass still put up a great fight at the end of a fishing rod, but with that being said, it is still important for sportsmen to know what is going on in the scientific community.

The tax revenue that is collected from fishing gear (in the form of an excise tax called the Dingell-Johnson Act, otherwise known as Federal Aid in Sport Fish Recreation Act) goes directly to education, hatcheries, habitat restoration, and research. In other words, important research, like the kind that’s discussed in this article, is an example of what the Dingell-Johnson Act supports. Each time we buy a new fishing rod, we help further scientific study that helps keep our fish populations strong and healthy.

More importantly, scientific studies help fisheries departments in states like Oklahoma and Arkansas, consider how stocking programs affect native fish populations. For example, Oklahoma has stocked northern smallmouth bass (Micropterus dolomieu) in several reservoirs throughout the state. These non-native smallies have done very well in the cold and deep impoundments. However, as the years went by, ichthyologists became concerned that the introduced smallmouth were spawning with the native populations, specifically with the Neosho Bass. This was concerning for fishery departments because the non-native smallmouth was disrupting the genetic purity of the native strains. Whether or not this genetic admixing should be considered a detriment to native black bass is still hotly contested, but one thing is sure, once non-native genetics get introduced into a population of native fish, the effects are unchangeable.

As the discoveries of Kim, Taylor, and Near are discussed and debated, anglers will find themselves on different sides of the discussion. These conversations will be especially important as fishery departments weigh the pros and cons of stocking programs and the possibility of introduced species displacing the native ones.

Thinking back on our trip, it’s thrilling to know the bass we were catching are true natives to southeastern Oklahoma, whether they’re called Little River Bass or not. Knowing these fish have always swum in the rugged, boulder-strewn rivers of southeastern Oklahoma brings a smile to my face. Native fish have an important role to play in their home waters, and they are a valuable sport fish for any angler who loves fishing in wild and secluded waterways. In the case of the Little River Bass, these fish have existed in the Little River watershed for the last 1 million years, well before the arrival of humans to North America. This certainly adds to their allure. I’m glad I can add the Little River Bass to my catch-list.