Scientists and anglers had already recognized by 1932 that largemouth bass in peninsular Florida grew to a larger size and had different coloration than their northern counterparts. These differences, as well as other physical characteristics, were used to classify Florida largemouth bass as a distinct subspecies in 1949. Although each is recognized as a unique biological unit, the two subspecies (Florida bass [Micropterus salmoides floridanus] and northern bass [Micropterus salmoides salmoides]) freely interbreed. Florida bass have been widely introduced throughout the nation because of their potential for producing trophy-size fish. However, native populations of this subspecies are unique only to the central and southern portions of the Florida peninsula. As a result, they represent a natural resource that is both biologically unique and economically valuable.

Using protein electrophoresis to identify distinct genetic components (alleles), scientists from the Illinois Natural History Survey confirmed the subspecific status of the Florida largemouth in 1983. Based on their sampling, they concluded that populations of pure Florida largemouth bass likely occurred in all water bodies throughout central and south Florida, and that intergrade populations (natural hybrid populations containing a mixture of alleles from both the Florida and northern subspecies) occurred in water bodies located in the northern part of the state.

Moreover, at the American Fisheries Society's Black Bass Symposium, in 1999, Dr. Dave Philipp, one of the leading fisheries geneticists in the world, raised the issue that Florida bass might actually be distinctly different enough to merit classification as a separate species. Not only that but James Williams and George Burgess from the Florida Museum of Natural History also published in 1999 a description of the “shoal bass,” which is another closely related species of black bass found only in Florida.

From a practical standpoint, the issue of how different fishes are genetically has major importance to their fitness. Simply put a "fit" fish is more likely to have more "grandchildren." In other words, the progeny from a genetically "fit" fish will survive and propagate more successfully in the environment they adapted to than a less "fit" fish.

Why this is varies tremendously, but let's look at one scenario. Northern bass spawn later in the year than Florida bass. This enables them to avoid dangerously cold temperatures for the young fry (baby fish) and ensures the water temperatures have warmed enough that the plant community is blooming and subsequently that there is an abundance of zooplankton (microscopic animals that fry feed on). Since these situations occur earlier in Florida , due to our latitude, Florida bass appear to be genetically coded to spawn earlier. Moreover, so are the prey species such as bream and shad. Under ideal timing, a Florida bass spawns when the waters are warming and rainfall is raising water levels slightly. The shallow spawning beds then are assured that they won't be exposed by dropping water levels, and the flooding of terrestrial vegetation generates a zooplankton bloom that the fry can feed on. As the bass fry grow to a length of about one-inch, they begin feeding on small fish. If the bass spawn too late, the zooplankton bloom may be gone and the bass fry may find that what should have been their prey have not only already grown too large for them to eat, but also their prey may be large enough to eat the bass fry. We have also seen that when bass time their spawn so that there is a wealth of food for their offspring to get a quick early growth spurt from, those offspring survive in larger numbers and more of them tend to become trophy-sized fish. This is often the case following a lake restoration drawdown, or a high-water year that follows a drought. The result is that even if this one factor altering spawning times were impacted by intergrading Florida bass with Northern bass in the southern portion of Florida, it could have dire consequences.

In 1999, electrophoresis was used to analyze the genetic makeup of 60 largemouth bass collected from Lake Istokpoga and 60 bass collected from Lake Parker. Only Florida bass alleles were found in the Lake Istokpoga samples, indicating a pure population of the Florida subspecies. Six (10%) of the largemouth bass collected from Lake Parker had genetic material from both the Florida and northern subspecies, indicating an intergrade population. Since both lakes are located in south-central Florida we expected to find pure populations of the Florida subspecies in each. The presence of northern largemouth bass alleles in Lake Parker has been a cause for concern among many fisheries biologists in the Fish and Wildlife Conservation Commission. We do not know if, or how, the performance (i.e., reproduction, growth and survival) of Florida largemouth bass will be affected by the introduction of northern alleles in Florida populations. The genes represented by the northern alleles may take hundreds, if not thousands, of years before they disappear from the population. This could alter the unique character of Lake Parker largemouth bass.

Many of Florida's lakes and ponds have dried completely due to the severe drought conditions over the past several years. We are concerned that when these water bodies re-flood, there will be tremendous demand for stocking largemouth bass. Private pond and lake owners from as far south as Fort Lauderdale are already importing largemouth bass from out-of-state fish dealers from as far away as Arkansas. Since there are currently no restrictions relating to the subspecific status of imported bass, many, if not most, of these fish are not the pure Florida subspecies. Because of Florida's topography, there is a very real potential for escapement of these fish into public waters during flood events. In addition, we have historically allowed lake associations to stock public waters with largemouth bass without specifying the subspecific status.

We are initiating a three-year study on largemouth bass genetics to determine the statewide distribution of pure Florida largemouth bass and intergrade populations. Preliminary results from this study should give us a better idea of the extent of the problem and the urgency with which we should take action. We plan to sample 50 public water bodies throughout Florida. Due to concern about private pond and lake owners importing northern largemouth bass from out-of-state, we will also be sampling privately stocked waters. The results of the privately stocked waters should become available by early spring 2002. We are also planning studies to evaluate performance differences between Florida and intergrade largemouth bass in selected study lakes.

Increased emphasis on genetic studies, studies of bass diseases and parasites, and research to optimize stocking success for largemouth bass are all parts of Florida Bass Conservation Center (click here for more details, including the option to express your opinion or make a donation) plans (FBCC). In addition, if the proposal is funded, the FBCC will have a new climate-controlled spawning room and raceways that will enable scientists to produce bass at the best possible moment for stocking in various Florida waters to maximize their survival and growth potential.