Bits & Pieces: Bass Genetic Breakthroughs & Windy Walleye Chops

This article originally appeared in the August / September 2021 issue of In-Fisherman.

Select Science: Bass Genetic Breakthroughs

In the late 1940s, ichthyologists Reeve Bailey and Carl Hubbs described the Florida bass as a subspecies of largemouth bass, simultaneously laying out the range for Florida (peninsular Florida) and northern largemouth bass (much of the eastern U.S.).  They also noted an intergrade/hybrid zone composed primarily of the state of Georgia. Publication of Dr. Dave Philipp’s genetic analyses of largemouth bass, published in the 1980s, indicated that Florida genetics were far more widespread than previously believed. Intergrade bass were more common, likely due to widespread stocking of Florida bass given their growth characteristics. But Bailey and Hubbs’ original distributions were accepted as the native ranges, before the impacts of stocking.

Fast forward 40 years and the Bailey and Hubbs map largely still stands unquestioned. Until now, it’s been generally thought that largemouth bass from a wide area of the Southeast represent genetic intergrades of northern and Florida largemouth bass (though Florida bass are now considered a species, not a subspecies as previously thought). Florida bass were restricted to southern and central Florida. But new genetic techniques have enabled better discrimination of genetic backgrounds (genomes), and allowed more samples to be tested more quickly and less expensively than ever before.

Dr. Eric Peatman, Professor of Fisheries at Auburn University, has headed the Southeastern Fish Genetics Cooperative since 2014 and has been coordinating analysis of genetic samples from rivers, reservoirs, ponds, and hatcheries to sort out the genetics of black bass species. “We look for ‘genetic signatures’ of sampled fish to define their heritage,” Peatman says. “You could consider it a version of ‘ancestry.com’ or ’23andMe’ for bass. As we examine more samples from more locations, our ability to define genetic backgrounds gets more precise.”

One of the clearest trends in Peatman’s recent analysis involves the range of Florida bass. “While the native range of that species was thought to be limited to central and southern Florida, it appears now that it’s actually much larger,” he says. “Florida bass genetics are dominant in most Georgia waters south of the Fall Line, as well as along the Atlantic Coast drainages as far north as North Carolina. In Alabama, we’ve found no northern largemouth bass, but mostly intergrade fish. Tennessee has a few waters with pure northern bass, but mostly intergrades as well.”

Peatman’s findings bring focus on the identity of George Perry’s world record (now officially tied), caught in 1932 in the Ocmulgee River of southeastern Georgia. “Through analysis of genetic markers we’ve more recently discovered, it’s most likely that Perry’s record fish was a Florida bass,” he says. “In those coastal rivers, pure Florida bass dominate. In the St. Mary’s River of Georgia, for example, it’s essentially 100 percent ­Florida bass.

“We now recognize three main genetic lineages within the largemouth bass group—northern largemouth bass, Florida bass, and one radiating from the Mobile Delta fish. These are distinct, but the genetic types have mixed in unique ways throughout this region of the Deep South. The Mobile Bay strain made inroads into inland systems during ancient periods of high sea levels that enabled further migration and mixture.”

While these revelations are interesting scientifically, they also have implications for stocking of private and public waters, official stock transfers among populations of the various black bass species, and even regulations. “Various genetic types and mixes have important performance differences, such as growth rate, catchability, and maximum size and age that could be managed by regulations fine-tuned to the population,” Peatman points out. Stay tuned for more revelations as this genetic work proceeds.

–Steve Quinn

Weather Connections: Wind and Walleyes

Many anglers believe that strong wind creates strong currents that force bait­fish to downwind shores, and that shores hit by wind produce the best catches. The strongest winds seldom create flows over one mile per hour, however. Wind creates more rapid flows only when shorelines or underwater structures like neck­down areas, saddles, and points constrict the flow.

Wind generated ripples and waves oxygenate surface layers of water by constantly stirring downward water that has contacted air. An uneven water surface also breaks up underwater light, creating a flicker that hides the movement of larger fish. These condi­tions are favorable to feeding success by walleyes and other predators, often stirring an active bite. Strong waves can, however, make fish sea-sick. As a result, large waves force walleyes and preyfish deeper.

Currents move plankton, and plankton concentrations attract pelagic baitfish like shad, smelt, alewives, and herring. But long periods of wind from a constant direction are needed to build major concentrations of plankton, and thus draw baitfish, to down­wind shores. Daily wind shifts are not good guides to the location of plankton, prey­fish, or movements of walleye schools. Long periods of prevailing winds are necessary to create downwind bait concentrations.

Good catches may result from fishing downwind shores as winds make daily shifts. Walleyes with home ranges on shorelines recently hit by the wind often become more active and catchable when the surface is roiled, which improves hunting conditions. But to identify spots that may hold the largest concentrations of active walleyes, primarily consider the prevailing wind direction.

–Ralph Manns

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