Largemouth Bass nest angling study

For years, bed fishing has been a controversial subject among the bass angling community. Largemouth bass nests can typically be seen from the surface as cleared patches near structure, and fishing these nests give anglers a greater chance of landing Florida’s most popular sport fish. Aggressive male bass protect their young from predators like bluegill and other panfish, but what happens to the eggs and hatchlings at the nest when dad is caught by an angler? While the adults are off the nest, predators will eat the eggs and bass hatchlings. Florida anglers expressed concerns about the effects of bed fishing on future generations of largemouth bass, so the FWC took action.

bass underwater with young fish
Male bass guarding their offspring exhibit aggressive behavior during nest encounters to protect their young.

Over the last four years, FWC freshwater fisheries biologists studied the effects of bed fishing on Florida’s largemouth bass populations. Every experiment needs a control and variable, so researchers used hatchery ponds and small natural lakes in the Ocala National Forest to study the effects of bed fishing on largemouth bass. The first two years of the study were completed at the Florida Bass Conservation Center in Sumter County, where the hatchery ponds are located. Each mature bass stocked in hatchery ponds received a tag and fin clipping for identification so researchers could track their parental contribution using genetic analysis. Before bass were released into the ponds, hatchery staff placed brush and concrete blocks in the ponds for added spawning habitat and to simulate a natural lake. Stocked fish were added to the ponds to provide food for the bass, and nest predators were added as a way to simulate a natural water body as best as possible.

man on boat
A biologist collects bass eggs from an active nest for DNA analysis.

After the fish were released and fully acclimated to the controlled hatchery ponds, biologists performed snorkel surveys to count, mark and track the bass beds. After beds were located, biologists collected five to ten eggs from each active nest for DNA analysis. Using the DNA data from eggs on a nest, biologists tracked how many times each individual male and female bass spawned throughout the spring.

Half of the controlled ponds were fished, and every nest located during the snorkel surveys was fished to simulate a worst case scenario. Caught bass were removed from the nesting area for one hour to observe the impact, and after one hour the fish were safely returned to the pond. The other half of the ponds were never fished and only observed on schedule. In the fall, the ponds were drained and all the fish were collected. Using genetic analysis of fin clips taken from all young bass documented during the year, and comparing it to the known adult bass in the pond, biologists identified which mature males and females contributed to the year class produced. With the angling data, biologists also determined if fish that were caught during the study successfully contributed young bass or if it was only fish that were not caught that contributed.

The only effect bed fishing had was under high fishing pressure. Under high angling pressure, fish may not spawn as many times as in unfished populations. This result was only seen in the relatively small (one acre) hatchery ponds, however the number of young bass produced for that year did not decrease. Bass caught multiple times went on to contribute as much as fish that were never caught.

Over the final two years, this study was repeated with slight alterations in small natural lakes in the Ocala National Forest. Researchers looked specifically at individual nest success rates in the wild and determined that bed fishing has very little impact on the numbers of next generation of bass produced and how successful individual nests are. Fished or unfished, only 30 percent of all wild bass beds succeeded in this study, which was similar to nest success rates in hatchery research ponds.

It’s important to note that these findings apply to largemouth bass in Florida. Bass within the state have a longer, warmer spawning season that allows for multiple spawns. The same may not be true for northern largemouth bass populations due to different environmental factors.

Anglers around the state made this study possible by making their voices heard. Bed fishing and its effects on the fishery was a top priority for many stakeholders, and our freshwater fisheries biologists provided data the FWC needed to better understand and address this important topic.