Alabama Largemouth Bass Genetic Enhancement
Alabama Wildlife & Freshwater Fisheries Division (formerly called the Game & Fish Division) is dedicated to providing anglers with high quality bass fisheries throughout the State. Harvest regulations are often utilized to manage fish populations but another management opportunity is through genetic enhancement of native populations. Typically, hatchery-raised fingerlings that posses certain desirable characteristics can be introduced into reservoirs, and if they survive to reach sexual maturity, will interbreed with the native bass and pass those superior genetic traits to their offspring. When successful, these traits can persist in the population and crate a “new breed” of bass that can offer anglers a more satisfying angling experience.
The Florida Largemouth Bass is a sub-species native to the State of Florida that has always been held in high esteem by bass anglers for its tendency to attain larger sizes than the Northern sub-species found throughout most of the Country. However, anglers often overlook the undesirable traits associated with this sub-species that is far less aggressive and more difficult to catch than its Northern counterpart.
State Game and Fish Agencies Nationwide have experimented with the introduction of the Florida sub-species into their native populations; but, the success of this strain outside of its evolutionary range has been highly variable due to variations in species interaction, water quality, habitat, and climate. However, carefully calculated public water stockings can sometimes introduce certain desirable genetic qualities into a native fish population. The intent of Alabama’s largemouth bass genetic enhancement program is to introduce the superior growth characteristics of the Florida sub-species, while minimizing its contribution of “lockjaw” genetics.
Although it Requires Far More Than Just Superior Genes to produce high quality bass fisheries, it is one of the few variables that biologists can sometimes manipulate to achieve certain goals for a bass population. The following is an account of the evolution of Alabama’s Florida largemouth bass stocking and genetic enhancement efforts.
During the Late 1960s and Early 1970s, the Alabama Game & Fish Division began experimenting with Florida strain largemouth bass stocking in a number of its State Public Fishing Lakes. Into the 1970s, the majority of the stockings continued in these lakes. The Division raised a limited number of fingerlings at the Spring Hill Fish Hatchery near Mobile, but secured the majority of its fish from the Welaka National Fish Hatchery located in the Florida panhandle.
During the Late 1970s and Early 1980s, the Alabama Game & Fish Division made its first attempts to offer Alabama’s anglers a legitimate opportunity to reap the benefits of the Florida strain of largemouth bass in the state’s public reservoirs. During this time, the Division stocked pure Florida strain fingerlings into several newly constructed reservoirs, such as the Bear Creek chain of lakes in Franklin County, and Gainesville and Aliceville reservoirs on the Tombigbee River system in West Alabama. Lake Harris on the Tallapoosa River was also stocked heavily while it was being impounded.
Because These Reservoirs Were New Impoundments being filled for the first time, they contained a limited number of naturally spawned, northern largemouth bass, and abundant habitat, which offered the stocked Florida strain fingerlings a better opportunity to gain a significant competitive advantage over the native, Northern strain bass.
During the 1980s, the Division took a “Johnny Appleseed” approach to Florida bass stocking, distributing all the fingerlings it could produce in its hatcheries to as many reservoirs as possible.
Prior to 1990, the Division conducted a number of genetic assessments in its State Public Fishing Lakes, and also funded genetic research on its public reservoirs, which was carried out by the Auburn University Fisheries Department. This research was intended to evaluate the stocking success in those water bodies. The results of these studies revealed valuable information that helped to guide the Division’s fisheries biologists through the early evolution of Florida bass stocking in Alabama.
What They Learned was that their stocking efforts in large reservoirs where stocking rates ranged from 1-2 fish per acre had been largely ineffective. Meanwhile, many of the stockings in the small Public Fishing Lakes where stocking rates ranged from 75-100 fish per acre resulted in an increase in the frequency of Florida genes in the bass populations.
Based Upon Knowledge Gained from these initial genetic assessments, the Division’s fisheries biologists altered the reservoir stocking strategy during the 1990s. Since its hatcheries had a limited capacity to produce Florida bass fingerlings, the Division could not produce enough fish to stock large reservoirs at the same rates it did in its small State Public Fishing Lakes. In order to maximize the potential to effect a positive shift in the frequency of Florida genes in its populations, reservoirs that were thought to provide the best possible habitat for Florida strain largemouth bass were selected for more intensive stockings. Furthermore, the available fingerlings were concentrated into isolated areas of each reservoir to more closely simulate the stocking rates that had been necessary to achieve success in its State Public Fishing Lakes.
Florida Largemouth Bass Stockings on Popular Reservoirs during the 1980s
The Biologists Chose Lake Guntersville to evaluate the innovative stocking strategy, and for three consecutive years from 1992-1994, an area of North Sauty Creek was stocked with pure Florida strain largemouth bass. The total number stocked was over 380,000 fish. Subsequent genetic assessments revealed that the Division’s new stocking strategy had successfully introduced Florida genes into the population of bass in that creek. The biologist’s theory that Florida bass genes could be introduced into the population if pure-strain fingerlings were stocked at high enough densities to overwhelm and out-compete the naturally spawned northern fingerlings had been correct at Lake Guntersville.
Based Upon This Initial Triumph, the Division began duplicating its efforts on several other reservoir bass populations; each of which was followed by a genetic assessment to evaluate success. The stockings in these reservoirs were met with mixed results. Populations in Guntersville, Lay, and Wheeler all experienced significant positive shifts in the frequency of Florida genes, while the efforts at Demopolis, Tuscaloosa, and Smith had all been unsuccessful. From this very limited amount of work, it appears that the older, less fertile impoundments with a scarcity of vegetation were less likely to benefit from Florida strain bass stockings.
Intensive Stocking of Florida-Strain Largemouth Bass
|Bear Creek Res.
|French & Birdeye Creek
|North Sauty Creek
During the 21st Century, the Alabama Wildlife & Freshwater Fisheries Division dedicated more pond space on its hatcheries to the production of Florida largemouth bass fingerlings and can now produce up to 500,000 fingerlings annually. Division biologists have continued to follow this same approach to Florida bass stocking and will be introducing them into prime areas of reservoirs thought to have characteristics conducive to the sustained production of Florida largemouth bass. Aside from these stocking efforts, biologists have been focusing on the performance of the populations where Florida genes have been successfully introduced.
The Presence of Florida Genes in a bass population is of little consequence to the anglers unless it translates into more big bass being caught. So, in an effort to measure the performance of largemouth bass in the lakes where stocking was deemed a success, biologists took the next logical step, which was to compare the presence of Florida genes in big angler-caught bass to those fish in the population at large.
During March of 2010, Division fisheries biologists obtained genetic material from 37 bass over seven pounds that were caught by tournament anglers from Lake Guntersville. In May of 2010, they also obtained genetic material from big, tournament caught bass at Lay Lake. At press time, the genetic assessments of these big bass had not yet been completed. If the results show that these big bass had a higher incidence of Florida genes than bass in the population at large, it will be clear that the Division’s efforts to enhance the genetics of Alabama’s largemouth bass populations has resulted in anglers catching more big bass.
Obviously, Answers to a Wealth of Questions ultimately determines the success or failure of a genetic enhancement program, but it is apparent that the Alabama Wildlife & Freshwater Fisheries Division has its program focused on enhancing good bass fisheries. Refining our public water stocking strategies and determining which populations of bass are most likely to respond positively to Florida bass stocking will ultimately allow biologists to maximize the benefits that can be afforded to Alabama’s bass anglers.