What to know about… Restocking Lake Yvette.
Fishing is indeed a popular recreational activity in Florida, with numerous small natural and manmade ponds scattered throughout the state. Proper management of these ponds can offer excellent opportunities for fishing, waterfowl hunting, and bird watching. Common fish species found in Florida fish ponds include largemouth bass, bream (bluegill and redear sunfish), and channel catfish. While the composition of fish may vary across lakes, these guidelines generally apply to most bodies of water. Ponds can be managed intensively to maximize fish production while also attracting wading birds, waterfowl, and other wildlife. However, conflicting uses such as swimming, residential development, drainage, and irrigation can pose challenges to fish and wildlife management. It is essential to address these conflicting uses when establishing a comprehensive pond management program.
It is necessary to have an understanding of basic aquatic ecology to manage a pond properly. Ecology is the study of relationships living things have to each other and their environment. These relationships frequently operate at a complex level, where a change in one factor can influence many different organisms and their habitats in a variety of ways.
At the bottom level of the simplified food pyramid are various species of algae. Algae are microscopic plants that use nutrients and sunlight to produce food through photosynthesis. Zooplankton, small free-floating animals, occupy the second level, feeding on some types of algae. Organisms in the top four levels of the pyramid typically prey on organisms from the lower levels. The capacity of a pond to sustain numerous organisms in the upper levels relies on the resilience of its food base depicted by the lower levels.
In ponds, humans, otters, alligators and some wading birds are the top predators. Largemouth bass are the top fish consumers (predators) that feed on insect-eating fishes such as bream, shiners and minnows. Some ponds may support gizzard and/or threadfin shad populations. Both feed on plankton, and are important prey for bass. The objective for most ponds is to establish a simple predator-prey relationship using largemouth bass, bluegill and redear sunfish. Wildlife will use the pond and shoreline for watering, feeding and hiding from predators.
Algal production in waters is constrained by nutrient availability, particularly nitrogen and phosphorus. Ponds with low nutrient levels are termed infertile, yielding minimal aquatic life. Such waters tend to be visibly clear and sustain a sparse fish population. In contrast, moderate nutrient concentrations create fertile waters capable of supporting more abundant fish populations than infertile ponds. The presence of ample food organisms in fertile ponds leads to a greater number of sport fish. Fertile waters often exhibit a greenish hue due to elevated algal levels.
Excessive fertility disrupts the food chain by channeling too much energy into algal production. During daylight periods, algae cells produce oxygen required for respiration by fish. When sunlight is not present (night or overcast skies), oxygen production by algae is reduced. Dense algal blooms will deplete dissolved oxygen (DO) during periods of limited sunlight, and fish kills may result. Fish kills caused by low DO levels are most common during warmer months when algal concentrations are highest and extended periods of calm weather reduce the exchange of atmospheric oxygen at the pond's surface. The figure shows a typical 24-hour DO cycle and during 12 months when fish kills are most prevalent.
Waterbodies in a watershed can receive nutrients from a variety of sources, both human-induced such as agricultural practices, lawn fertilizers, and urban development, and natural sources like nutrient-rich soils and decaying vegetation. Pond owners might need to eliminate or redirect nutrient inputs to prevent over-fertility.
Fish Management Strategy
Once you have designed your pond and addressed water quality and aquatic plant management concerns, the next step is to determine a fish management strategy. Evaluate your desired species, level of management intensity, and realistic expectations. Popular fish for stocking ponds include largemouth bass, bluegill, redear sunfish, and channel catfish, while triploid grass carp can be stocked to help control problem aquatic vegetation (Figure below, illustrations by Duane Raver, Jr., triploid grass carp by Ted Walke). Then design and implement a sound fish management program. Seek several sources of advice before making any stocking decisions. The FWC website or the Regional Office can provide a list of fish suppliers in your area. However, state-operated hatcheries do not stock privately owned waterbodies).
Establishing a Fishery
When considering stocking a pond, there are three primary reasons to take into account:
The pond is new and lacks any fish population.
Undesirable species have infested the pond.
An established fish population has become unbalanced, with either prey species (such as bream) or predator species (such as bass) dominating disproportionately, hindering the reproduction of the other species.
An unbalanced fish population may stem from various factors like fish kills, improper harvesting, incorrect stocking ratios, poor water quality, or a combination of these issues. It's crucial to note that introducing fingerling game fish into an existing fish population is generally ineffective due to low fingerling survival rates.
For success, stocking larger juveniles or one-year-old fish can be promising, provided there is sufficient habitat to support their survival. In cases of unbalanced or undesirable fish populations, renovation (complete removal of fish) and subsequent restocking is often the most practical approach to rectify the situation. Regardless of whether the pond is newly constructed or renovated, timely stocking of fingerling fish is advised to prevent the inadvertent establishment of an undesirable fish population. Keep accurate harvest records so as the population becomes depleted, you can stock more fish.
You can establish a largemouth bass/bream fishery in a new pond by stocking 250-500 bream fingerlings per acre in the fall, followed by 50-100 largemouth bass fingerlings per acre the next spring. Numbers stocked vary, depending on pond fertility. The bream stocking should consist of approximately 70 percent bluegill and 30 percent redear sunfish. This stocking schedule will allow bream to grow and reproduce. Some of their offspring are then eaten by developing bass. You can begin bass fishing 18 months after stocking largemouth bass fingerlings. Bluegill and redear sunfish harvest should begin eight months after stocking.
Restocking is not usually required since bass and bream reproduce naturally. In some ponds that are infertile or acidic, bass fingerlings should be stocked again one year after the initial stocking. This is needed when bass grow slowly and fail to reproduce after their first year. If properly managed, a largemouth bass/bream fishery can sustain itself indefinitely. You can stock catfish along with bass and bream. Stock fingerling catfish (100-500 per acre) with bass in the spring. Once bass have established and grown, it is necessary to stock larger (>8 inches) catfish since bass will consume catfish fingerlings.
In fertile ponds that support threadfin shad, it may be desirable to stock hatchery-reared sunshine bass. These fish are a cross between striped bass and white bass. They will not reproduce, so you will need to restock them. Overstocking sunshine bass or introducing them into infertile waters will create competition with largemouth bass and should be avoided.
If shad are stocked as prey, only use threadfin shad; their limited growth is best suited as a prey species for largemouth bass, sunshine bass, and black crappie, if present. Fish species you should not stock are common carp, brown bullhead, black crappie (in most situations), Georgia Giants, Nile perch (tilapia), and any non-native or aquarium species. It is unlawful to stock exotic species or native species from hatcheries residing outside the state without FWC permission. While black crappie are a popular game fish in lakes, they tend to overpopulate and cause unbalanced populations in smaller ponds.
Fishery Maintenance
To maintain a properly balanced bass/bream fishery, it is crucial to manage the population carefully. Overharvest of bass or underharvest of bream can disrupt the initial stocking balance, leading to poor fishing outcomes. Stunted bream, characterized by small size and large eyes, signifies imbalance within the population. To address stunting, a strategy of limiting bass harvest while increasing bream removal is recommended. Aim to remove 10 pounds of bream for every pound of largemouth bass, being cautious not to deplete bass stocks excessively in ponds under 5 acres. If an overabundance of small bass is observed, consider harvesting those under 12 inches while practicing catch-and-release for larger individuals. In cases of excessive bluegill populations, introducing adult bass may help restore the predator-prey equilibrium, preferably in small ponds with adequate bass acquisition. Prioritize stocking adult bass measuring 10-12 inches at 10 to 15 per acre, as fingerling bass stocking is ineffective in this scenario.