Fisheries Management

AS SEEN IN POND BOSS MAGAZINE, Written by Director of Fisheries Management, David Beasley

Catch-and-release is a common Largemouth Bass management strategy, and is one that both sounds and feels good to a great deal of people. Oftentimes, fishermen can think back to the days when dad or grandpa took them fishing, instilling the mindset of releasing any fish that they were not going to eat back into the water. Over the past few decades, this management practice of releasing all bass back into the water has become a contentious topic among anglers. Generational changes in human culture and behavior have shifted many anglers’ focus towards catching bigger bass for fun, and away from high catch rates or fishing to put a meal on the table.

This common practice of releasing all bass has both positive and negative aspects, and significantly impacts angler catch rates, as well as fish growth rates. As a result, it should only be applied when both the stakeholder goals and the bass population dictate. The strategy works best when kids and adults desire a fast-paced angling experience, where hungry 8-14 inch bass are abundant and aggressive. This is because catch-and-release helps ensure the fishery is full of small and intermediate size Largemouth Bass that are oftentimes hungry due to limited forage relative to the number of bass. An added benefit of overpopulated small bass is that large panfish such as Bluegill are typically available for anglers to catch. In general, panfish between 7-10 inches can be caught reliably in these fisheries, enhancing the opportunity for fast-paced fishing.

Although it would seem that the forage population can provide plenty of food for these bass, in reality each bass requires a great deal of forage fish to grow to a size beyond 14-16 inches (two to three pounds). If seeking a fishery that produces numerous bass of 3-5 pounds or greater, you will need large populations of forage fish each year. In nearly all scenarios, if largemouth bass are left unchecked through minimal or no harvesting, they will naturally maintain too high of a population relative to the biomass of forage fish that are grown annually. This lack of sufficient forage per bass results in a great deal of 8-14 inch bass, with few, if any, surpassing that size.

If anglers desire to catch bigger bass, they need to accept the fact that the bass population must be maintained at lower than normal/natural, thus providing the remaining bass enough forage to grow. To accomplish this, a selective harvest program targeting small and intermediate-size bass needs to be implemented. Harvesting each year is necessary, since the moment you stop, their population will expand, and the fishery will fall back into its overpopulated rhythm.

If interested in implementing a selective harvest program, how many should you harvest? What data should you look at to know if you have harvested enough? First off, goals for angler catch rate and bass sizes need to be defined, and stakeholders need to agree on those goals. Next, the fisheries biologist running point on the selective harvest program will need good, reliable data.

Angler catch data is equally as important as electrofishing data, improving the odds of accomplishing management goals as quickly as possible. During each fishing trip, fishermen should collect data on how many bass were caught, how many were harvested, how many people fished, how long they fished, the date, and the length of each fish caught, rounded down to the nearest inch. (i.e. a 12.5 inch fish would fall into the 12 inch length bin). Using this angler data, key information can be analyzed, including length-frequancy showing the population’s size distribution, and the catch-per-unit-effort (CPUE) that shows how many bass are caught per hour of angling. Filtering this data by date allows biologists to compare spring to spring, or fall to fall, over the years. Knowing how many bass were harvested, and what size is one of the more critical details gained in this process. 

The correct number of bass harvested will vary from waterbody to waterbody. The best harvest strategy is to remove the targeted number of bass prior to the spawn each year. If that is unrealistic, try to harvest them by mid year. The longer you wait until you take them out, the more forage they are going to eat, which has a noticeable negative impact over the years. 

It is critical to know that the initial harvest goal is not typically the correct number. Creel data and electrofishing data provide insight as to if enough bass have been removed. An example of this is a 550 acre lake in South Florida. It was overrun with small bass 10-12 inches long that were noticeably underweight. Rarely, were bass greater than 15 inches when caught. The goal was to improve the size of the bass, providing anglers with the opportunity to catch quality bass. It was unknown how many largemouth were in the system, but based on experience and the data available, we set the initial harvest goal of 3,000 measuring less than 15 inches in 2022. Two anglers, in particular, took the harvest program seriously, and removed 1,700 themselves. The remaining couple dozen anglers managed to only remove 600, bringing the total to 2,300. Although anglers fell short of that goal, the remaining bass in the lake responded well, shifting the size structure from 10-12 inches long, to 12-16 inches long in just 15 months. Ideally, they would have hit the initial harvest goal of 3,000, then assessed the data to determine if they should keep going; regardless, we gained valuable insight and proved to the anglers that they were on the right track.

The initial harvest goal of 3,000 fish stayed the same in 2023, although the size was increased to all bass measuring less than 16 inches. The goal was to harvest the bass by July 1st. That year, anglers relaxed their approach and did not fish enough. They severely missed their goal to harvest by July, and only harvested 2,030 by December 31. In January of 2024, the lake was electrofished. The size structure of the bass was nearly identical to the data collected 11 months earlier. Although this was negative news for the fishermen, that their efforts yielded no growth gains, it still provided good insight. The anglers went from believing it was going to be easy, to the reality that they would need to take their goals more seriously. The setback to the fishery’s trajectory is significant, but the hard lesson learned by the anglers may be enough to start changing their mindset.

For those anglers on the fence, liking the idea of selective harvest but concerned that they may remove too many bass, overharvesting rarely occurs by accident. Almost always, anglers harvest too few bass. In the rare scenario you do over harvest, the fishing typically slows for 12 months before returning to pre-harvest levels. The next generation of bass born would grow faster than the previous generations due to the lack of competition, resulting in young bass that are large for their age, and have an opportunity to reach larger sizes. For those who are serious about growing bigger bass, it usually makes sense to overharvest on purpose for this reason. 

So next time you catch one of those one pound bass that seem to be overpopulated, take a second to think about the impact that releasing it may have on the fishery. Whether your fishery is doing great or is in very poor shape, it is important that you adopt the right strategy based on your goals. In many cases, selective harvest is a strategy worth considering.