FWRI biologists discuss the factors that contribute to the growth of trophy-sized Florida largemouth bass.
|The journey to trophy size is an arduous one for many Florida largemouths.
Anglers from around the world travel to Florida for the opportunity to catch a Florida largemouth bass (Micropterus salmoides floridanus). The state is known as the Fishing Capital of the World in part because of the trophy-size largemouth bass that can be found in many different habitats, from one-acre ponds to large natural lakes, rivers and marshes. In general, trophy-size Florida bass grow faster than the general population. However, not all bass reach trophy status. Actually, chances are slim that any bass will grow to 8 pounds or larger. Trophy-size 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 bass have revealed several about these sought-after sportfish.
The most important factor influencing the occurrence of trophy-size bass is natural growth potential. Florida bass are genetically different and grow much larger than the northern largemouth bass. Scientists at the FWC’s Fish and Wildlife Research Institute (FWRI) have surveyed lakes and rivers across Florida to determine where genetically pure Florida bass populations occur. The FWC has established conservation programs to protect these populations.
Growth to trophy size also differs between genders. Female Florida bass grow faster than male bass and typically only the females grow larger than 8 pounds. Florida’s warm climate and long growing season also enhance the growth rates of largemouth bass.
Even with faster growth rates, it takes a while for Florida largemouth bass to reach its full potential, so survival is always a factor in becoming a trophy bass. The recorded ages of trophy-size bass have ranged from 4-16 years old, with an average of 10 years of age in Florida. But only a small percentage of largemouth bass live longer than 5 or 6 years, so reaching 10 years of age and trophy size is not the norm. Many factors can affect a bass’s odds of surviving long enough to reach trophy-size.
- Year One: During its first year of life, bass must not only find enough to eat, but also avoid being eaten by predators. Most fish do not make it through the first year.
- Anglers: Bass that survive the juvenile stages then have to avoid being caught and harvested by anglers. High rates of harvest, particularly for larger bass, lower the probability that fish will grow to trophy sizes. Slot size limits tend to allow more Florida bass to reach trophy sizes.
- Stress: For bass fortunate enough to find enough to eat, avoid predators and not be harvested, there are still threats to their survival. Stressors, such as low dissolved oxygen, can weaken their resistances 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 food 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’s ability to capture them. Also, the energy required to catch prey, caloric content of the prey, digestion rates, and the rate the fish burns the energy all influence bass growth rates. Diet studies demonstrate that big bass eat large prey items, so availability of prey such as large-sized chubsuckers, shads, sunfish, and tilapia may have an effect on the size a bass can attain.
|Clear, vegetated lakes can hold opportunities for trophy-minded anglers.
Habitat conditions also play a significant role in the production of trophy-size bass. Like plants, bass thrive in nutrient-rich environments. Water bodies that are naturally high in nutrients or have been enriched by human activities (e.g. agricultural runoff or phosphate strip mining) are more likely to produce trophy bass.
Clear lakes with good water quality and abundant aquatic plants also produce good numbers of trophy-size bass. For small bass, an abundance of aquatic vegetation provides cover from predators and supports a wide variety of prey like insects, crayfish and small fishes. In fact, the majority of bass reported to the FWC’s Big Catch Program the last 20 years were caught in lakes with heavy growth of aquatic plants.
Extreme water fluctuations also create habitats that produces trophy bass fisheries. Sometimes this happens naturally during cycles of droughts and other times it results from lake water levels (lake drawdowns). The flooding or reflooding of a reservoir produces the same results.
The journey to trophy size is an arduous one. As research continues, biologists will learn more about trophy-size 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 this prized sport fish.