The largemouth is an olive green fish, marked by a series of dark, sometimes black, blotches forming a jagged horizontal stripe along each flank. The upper jaw (maxilla) of a largemouth bass extends beyond the rear margin of the orbit. In comparison to age, a female bass is larger than a male. The largemouth is the largest of the black basses, reaching a maximum recorded overall length of 29.5 in (75 cm) and a maximum unofficial weight of 25 pounds 1 ounce (11.4 kg). The fish lives 16 years on average.
The juvenile largemouth bass consumes mostly small bait fish, scuds, small shrimp, and insects. Adults consume smaller fish (bluegill), snails, crawfish (crayfish), frogs, snakes, salamanders, bats and even small water birds, mammals, and baby alligators. In larger lakes and reservoirs, adult bass occupy deeper water than younger fish, and shift to a diet consisting almost entirely of smaller fish like shad, trout, ciscoes, shiners, and sunfish. Prey items can be as large as 25 to 35% of the bass's body length.
Studies of prey utilization by largemouths show that in weedy waters, bass grow more slowly due to difficulty in acquiring prey. Less weed cover allows bass to more easily find and catch prey, but this consists of more open-water baitfish. Paradoxically, with little or no cover, bass can devastate the prey population and starve or be stunted. Fisheries managers must consider these factors when designing regulations for specific bodies of water. Under overhead cover, such as overhanging banks, brush, or submerged structure, such as weedbeds, points, humps, ridges, and drop-offs, the largemouth bass uses its senses of hearing, sight, vibration, and smell to attack and seize its prey. It can sometimes hold up to five sunfish in its mouth. Adult largemouth are generally apex predators within their habitat, but they are preyed upon by many animals while young.
Largemouth are keenly sought after by anglers and are noted for the excitement of their fight. The fish will often become airborne in their effort to throw the hook, but many say that their cousin species, the smallmouth bass, can beat them pound for pound. Anglers most often fish for largemouth bass with lures such as plastic worms (and other plastic baits), jigs, crankbaits and spinnerbaits. A recent trend is the use of large swimbaits to target trophy bass that often forage on juvenile rainbow trout in California. Live bait, such as nightcrawlers, minnows, frogs, or crawfish can also be productive. In fact, large golden shiners are one of the best things to use to catch trophy bass, especially when they are sluggish in the heat of summer time or in the cold of winter. Largemouth bass are known to take any bait they consider alive.
There is a strong cultural pressure among largemouth bass anglers which encourages the fish's live release, especially the larger specimens. Largemouth bass, if handled with care, respond well to catch and release; many studies have shown specimens which have survived being hooked and released multiple times.
The Largemouth Bass has been known to exist in many of the lower 48 states of the U.S. Although it is most popular in the southeastern states, many different varieties of the largemouth bass can be found in the north and western regions.
Largemouth bass prefer to hold around cover such as logs, rock ledges, vegetation and man-made structures in clear, quiet ponds and lakes. Smaller populations can also be found in creeks, canals and other areas with dense vegetation.
Largemouth bass were originally distributed east of the Rockies, including many rivers and lakes in Texas. There are also limited populations in southeastern Canada and northeastern Mexico. Because of its importance as a game fish, largemouth bass have been introduced into many other areas worldwide, including nearly all of Mexico and Central and South America.