Largemouth Bass Harvest: An Essential Management Tool for Lake Owners
During the 1950s Dr. H.S.Swingle of Auburn University, after years of research, determined that stocking largemouth bass and bluegill was the best set of species to provide long-term fishing in ponds and small impoundments. This combination of bluegill and largemouth bass stocked at a 10:1 ratio provided stability and a “balanced” population.
Balance refers to a situation where both the bluegill and largemouth bass are reproducing and providing catches of harvestable fish of both species. Keep in mind that to this early generation of pond owners a harvestable bluegill was 4 ounces and a harvestable largemouth bass was less than a pound. This combination of stocking largemouth bass and bluegill at a 10:1 ratio was adopted by most game and fish agencies in the southeast during the early 1950s.
Today’s landowners have different objectives. They want quality largemouth bass fishing that includes catching high numbers of bass in the 2- to 4-pound range, with a reasonable possibility of catching a largemouth bass 8 pounds or larger. To obtain this type of fishery requires more than fertilizing and feeding.
Fighting Mother Nature
Dr. Rich Noble, retired fisheries professor at North Carolina State University says that largemouth bass management is a fight against Mother Nature. Noble stated, “In nature, largemouth bass populations tend to be dominated by small fish. For viability of the population it is an advantage to have large numbers of small reproducing bass rather than moderate numbers of large fish. Lake fertility doesn’t change the size distribution much. If we are going to have big bass, we have to get the food to them, and the small bass are a big problem preventing that.”
Carrying capacity of largemouth bass
To understand why these small bass are such a problem we need to look at the total pounds of fish a pond can produce and the changing relationships among largemouth bass, bluegill and other prey species. At a given fertility level, a pond supports predictable poundage of fish. This total poundage or carrying capacity is typically comprised of 25 percent bass. Biologists speak of a pond’s carrying capacity of largemouth bass in terms of pounds per acre. The total pounds of largemouth bass per acre is pretty consistent over time, even if the size composition of the bass population changes. Therefore, you can have a high number of small bass or a smaller number of larger bass.
Bass have optimum sizes of food fish (prey) that are needed for fast, efficient growth. Eating food smaller than the optimum size is inefficient because more energy is burned in catching small prey than is gained by eating it. Bass growth is dependent on prey growing to the right sizes to become optimum for each of the various sizes of bass in the population. High populations of small bass deplete the bluegill reproduction, leaving few bluegill to grow to the proper size for larger bass growth.
Correcting populations of small largemouth bass
How do we correct an overpopulation of small bass? The most economical and efficient management approach is to decrease the population of small bass by angling. The bass size structure can be shifted upward by aggressively removing the small bass. The total poundage of bass in the lake will not increase, but the remaining fish will grow larger.
What size largemouth bass should you remove? Typically, the bottleneck occurs at bass lengths of 10 to 16 inches. Largemouth bass within this size range are so abundant that they deplete prey needed for growth by larger bass. I usually recommend the pond owner start out removing all bass under 16 inches until an established harvest quota is met. Sometimes it is very difficult for anglers to remove bass that are 8 to 10 inches because it goes against their “catch and release” mentality. Also, if you catch a bass that is 18 inches or larger that is very skinny, take it out. It is also important to remove these bass in as short a time as possible. If the harvest is stretched out too long the bass will replace themselves.
Harvesting male largemouth bass
Although bass can be removed anytime of year to improve size structure, an excellent time to remove high numbers of bass is spring. Catch rates are usually highest in the spring and bass can be sexed this time of year. Since the females are the ones that grow larger and reach trophy size, it is to the pond owner’s advantage to remove as many males as possible. Males are highly vulnerable as they move into shallow water to prepare spawning nests and guard the young. Also, harvesting bass early will allow the forage (bluegill) to increase their spawning success, thus more food for the remaining bass.
As a general rule, most fishery professionals recommend the removal of approximately 30 pounds of bass per acre from a well-fertilized pond. This can be accomplished on a good weekend on a 2-acre pond. However, as the lake increases in size it becomes a challenge to harvest the quota of bass. I know of two lakes 75 to 100 acres in size that had 2,000-3,000 pounds of bass removed in one year by angling, so it can be done. It may require you to have a few tournaments with friends to get enough fishing pressure to accomplish your harvest goals.
What size largemouth bass to harvest
Selective harvest the largemouth bass population, just like fertilizing or feeding, should be continued year after year. The bass population, by nature, will continue to produce large numbers of small bass, which will be contrary to your goal of larger quality bass.
As the population responds to selective harvest the size needing reduction will change, typically requiring larger fish to be removed. If you started by removing fish less than 16 inches, after a few years you may want to move this up to 18 inches and under. Hook and line sampling can give a good indication of the size distribution of bass in the population, especially the overabundant size range.
Quality largemouth bass management is best achieved by the use of multiple management techniques– such as fertilization, feeding, stocking additional prey species, aeration, etc. However, harvesting bass by angling to thin the population is one of the most effective and least expensive management practices that can be initiated to produce quality bass fishing.