Biologists discuss what factors contribute to the growth of trophy-sized Florida largemouth bass.
Florida is renowned for offering anglers opportunities
to catchy trophy-sized Florida bass.
Anglers from around the world travel to Florida for the opportunity to catch a Florida largemouth bass (Micropterus salmoides floridanus). The state is recognized as the Fishing Capital of the World, in part because of the trophy-sized Florida bass (8 pounds or larger) that can be found in many different habitats in peninsular Florida, from 1-acre ponds to large natural lakes, rivers and marshes.
In general, trophy-sized Florida bass grow faster than the average bass in a typical population, and not all bass reach trophy status. Actually, chances are slim that any individual bass will grow to 8 pounds or larger. Trophy-sized fish are typically the old and rare members of the bass population, and many things must fall into place for them to reach this size. Decades of research on the Florida largemouth bass has revealed several things about the growth of these sought-after sport fish.
Natural growth potential is one of the most important factors influencing the occurrence of trophy-sized bass. Florida bass are genetically different and grow much larger than the northern largemouth bass. These two bass are so different that they could soon be classified as different species. Scientists at the FWC’s Fish and Wildlife Research Institute (FWRI) have surveyed lakes and rivers across Florida to determine where Florida bass populations occur, and the FWC has established conservation programs to protect the genetic purity of these populations.
Growth to trophy size also differs between genders. Female Florida bass grow faster than male bass, and usually only females grow larger than 8 pounds. Florida’s warm climate and long growing season also enhance growth rates of Florida bass.
Even with faster growth rates, it takes years for a Florida bass to reach its full potential, so survival is always a factor in becoming a trophy-sized bass. The recorded ages of trophy-sized bass have ranged between 4 and 16 years old, with an average of 10 years of age in Florida. But only a small percentage of largemouth bass live longer than five or six years, so reaching 10 years of age and trophy size is not the norm. Many factors, including the following, can affect a bass’ odds of surviving long enough to reach trophy size.
- Year one: During its first year of life, a bass must not only find enough to eat but also avoid being eaten by predators. Most bass don’t make it through this first year
- Anglers: Bass that survive the juvenile stages then have to avoid being caught and harvested (kept) by anglers. High harvest rates, particularly for larger bass, lower the probability that fish will grow to trophy sizes and reduce anglers’ chances of catching one.
- Stress: For bass fortunate enough to find enough to eat, avoid predators and not be harvested, there are still environmental threats to their survival. Stressors, such as low oxygen, can weaken their resistance to disease and infection, leading to natural deaths. All things considered, it is pretty difficult for a bass to survive long enough to reach trophy size.
When it comes to how feeding is related to bass growth, there is more to it than just the amount of prey available. The size and location of the prey affect a bass’ ability to capture them. Also, the energy required to catch prey, caloric (energy) content of prey, digestion rates and the rate at which a fish utilizes or burns energy all influence a bass’ growth rate. Diet studies demonstrate big bass eat large prey items, so availability of prey such as larger chubsuckers, shads, sunfishes, tilapias and crayfish may have an effect on the size a bass can attain.
Clear, vegetated lakes provide the right conditions
for bass to grow to trophy size.
Habitat conditions also play a significant role in the production of trophy-sized bass. Like plants, bass thrive in nutrient-rich environments that can support abundant food resources. Water bodies that are naturally high in nutrients or that have been enriched by human activities (e.g., agricultural runoff or phosphate strip mining) have a better likelihood of producing trophy-sized bass.
Clear lakes with abundant aquatic plants also produce trophy-sized bass. For small bass, an abundance of aquatic vegetation provides cover from predators and supports a wide variety of prey – insects, crayfish and small fishes. In fact, the majority of trophy-sized bass reported in the FWC Big Catch Program during the last 20 years was caught in lakes with heavy growth of aquatic plants.
Extreme water-level fluctuations also create habitats that support trophy-sized bass. Periods of low water levels allow lake bottoms to oxidize, which helps promote new plant growth. Then when water levels rise, these plants provide habitat and work as filters that improve water quality. Sometimes these water-level fluctuations happen naturally during cycles of droughts and rain, while other times they’re the result of management (lake drawdowns). The flooding or reflooding of a reservoir produces the same results.
The journey to trophy size is a difficult one. As research continues, biologists will learn more about trophy-sized bass and the factors that contribute to their growth. Science-based conservation will aid the preservation of Florida’s bass populations, helping ensure anglers continue to have opportunities to catch these prized sport fish.