Results of three genetic studies conducted on Florida largemouth bass released into Chickamauga Lake have all revealed some positive news for bass anglers, but with results that might be surprising, according to the Tennessee Wildlife Resources Agency.
TWRA Fisheries Division Chief, Bobby Wilson, made an in depth presentation on the subject during the December meeting of the Tennessee Fish and Wildlife Commission.
Largemouth bass collections by TWRA fish crews in 2010 and again in 2012 indicated the successful integration of Florida bass, the southern strain of largemouth, into the lake’s largemouth population. This past spring, the agency removed genetic samples from 50 trophy-sized largemouth bass caught by local anglers and tournament competitors.
Nearly all the fish were either a hybrid where the southern strain of fish had crossed with Tennessee’s native northern bass; or they were later generations of largemouth known by biologists as backcrosses.
None of the trophy fish from 2013, many eight pounds or larger, were the pure southern or northern strain of bass.
“We are excited about the results of the Chickamauga Lake Florida Bass Project,” said Mr. Wilson. “Our original goal was to increase the percentage of Florida bass genes to 15 percent and it is currently about 45 percent, but more importantly these stockings have led to a significant increase in the number of larger bass in the lake.”
Mr. Wilson credited local anglers and bass tournament directors for their participation in the TWRA study and their desire to see a trophy bass fishery on a lake where reservoir conditions have also likely helped produce headline-making catches from Chickamauga.
Of the 50 angler-caught largemouth sampled this year, 75 percent were hybrids and 25 percent were backcrosses, according to TWRA Reservoir Biologist Mike Jolley. Mr. Jolley headed all of the studies on Chickamauga.
“A backcross is created when hybrids or their offspring spawn with a pure Florida or pure northern strain of bass,” explained Mr. Jolley. “Interestingly, the pure Florida largemouth bass was not observed at all, which has been the common theme throughout this project. Hardly any pure Florida bass have been collected during any of our samples.”
While hybrids dominated the total number of fish that anglers caught for the 2013 genetic study, it was the backcrosses that dominated the agency’s collection of bass in 2010 and 2012 through electro fishing methods.
“Hybrids, which are thought to have more vigor and better growth rates, made up the majority of the big fish and were confirmed to have superior growth rates verses the native northern strain,” said Mr. Jolley, explaining why it was not surprising that a large percentage of the angler-caught fish were hybrids.
Bass collected during TWRA electrofishing studies represented a much wider range of bass sizes. However, every study indicated satisfying progress toward trophy bass management.
“Hybrids in the Chickamauga bass population have demonstrated better growth rates when compared to the native northern strain of bass,” said Mr. Jolley.
While the release of some two million southern strain of bass since the year 2000 have indeed indicated Florida bass can provide a boost to Chickamauga, not all reservoirs are created equally for trophy bass management, emphasized Mr. Jolley.
“Contributing factors have likely helped with the success of this program on Chickamauga,” said the biologist. “It is a large reservoir, with good aquatic vegetation, ample forage base, adequate size limits on bass, and consistent natural reproduction of bass. All of that has helped create a perfect storm for this very good outcome.”
While the TWRA wants to help maintain a trophy bass fishery on Chickamauga, limited hatchery space, limited sources of Florida Bass from other states, and the limiting factors on other reservoirs across the state will determine if and where other southern strain bass might eventually be introduced.
“When we started stocking Florida bass into Chickamauga more than 10 years ago we announced then that everyone needs to understand that there are limitations to where and how many fish we can stock in other bodies of water,” said Mr. Wilson. “That still holds true today.”