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  4. 2008
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The Largemouth Bass

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The largemouth bass (Micropterus salmoides) is a member of the sunfish family. This family of fish contains many species, including smallmouth bass (Micropterus dolomieu), bluegill (Lepomis macrochirus) and crappie (Pomoxis spp.). Two subspecies of largemouth bass (LMB) are typically recognized, Florida and northern (native to Oklahoma and Texas). Many people like to stock their ponds or lakes with Florida-northern crosses because of their potential for increased growth. Unfortunately, this extra growth only occurs in the first generation crosses. Resource managers also stock just the Florida subspecies hoping for a larger than average native bass. A pure strain Florida LMB fishery will be compromised if native bass are in the pond before stocking or are introduced accidentally or intentionally. With proper management, native LMB can grow to 12 pounds or more. Regardless of the stocked subspecies, available forage (baitfish) is essential to growing big, healthy bass.

Bluegill make an excellent forage base for LMB due to their ability to reproduce at incredible rates. During one summer, a female bluegill can spawn three times releasing 2,300 to 81,100 eggs per spawn. This rate of reproduction is necessary to maintain adequate bass forage in a balanced bluegill/largemouth bass fishery.

LMB have the ability to surpass 2 pounds with unlimited forage during the first year of life, but about a half-pound is normal. For annual maintenance, a LMB requires about 5 to 7 pounds of forage per pound of body weight. If you have a 5 pound LMB in your pond, it will need 25 to 35 pounds of forage to maintain its weight for one year. To increase a LMB by 1 pound (5 pounds to 6 pounds) requires 10 pounds of forage more than the annual maintenance. To capture forage fish, LMB feed mostly by sight. Water clarity should be 15 to 32 inches for ideal growing and feeding conditions. Muddy or exceptionally clear water (3 feet or more) normally inhibits the growth and reproduction of LMB. The ability of a LMB to feed effectively influences its ability to build fat reserves, increasing the odds of a successful spawn.

LMB can spawn at 1 year old, but typically begin spawning after they reach 9 to 10 inches long. During spring when the water temperature stabilizes above 60 degrees F, males select a nest site. The spawn usually begins with water temperatures of 65 to 75 degrees F in water 1 to 4 feet deep, but nesting attempts have been observed in clear water up to 20 feet deep. To construct the nest, the male sweeps away debris, creating a shallow circular depression about twice the length of his body. Materials such as sand or gravel are chosen as preferred nest sites.

Once the nest is completed, the male begins searching for a female. After the male finds a female, the two circle the nest. The period when the female releases eggs and the male releases sperm is called spawning. Females usually release only a portion of their eggs in the first spawn and the remaining eggs in one or more successive spawns. Females average 4,000 eggs per pound of body weight, but the number can be quite variable. Larger females typically have larger eggs and thus larger fry (newborn fish), but they tend to have fewer eggs per pound of body weight. Immediately prior to spawning, eggs make up approximately 10 percent or more of a female's body weight. It is common for one male to spawn with multiple females.

If the nest is successful, the eggs hatch in two to ten days, depending on water temperature. Males guard the fry until they disperse, which can be as long as two weeks. Unfortunately, many males do not survive the spawning season because of the stress of spawning and not eating. Males spend the majority of their time and energy defending the nest, sweeping away sediment and guarding their young.

Fry feed on the yolk sac of the egg for the first few days of life. Afterwards, fry begin feeding on zooplankton (microscopic animals). Fry disperse a few days after this. Once they have reached 1.5-2 inches long, they add insect larvae and fish to their diet.

Steven Smith serves as a wildlife and fisheries consultant at Noble Research Institute, where he has worked since 2006. He received a bachelor’s degree in wildlife and fisheries ecology and a master’s degree in rangeland management and ecology from Oklahoma State University. He grew up on small family cow/calf operation in central Oklahoma. His areas of interest are prescribed fire, especially growing season fires, and managing plant communities for livestock forage and wildlife habitat.