Largemouth Bass (Micropterus salmoides) - Introduced

A typical, 14-inch adult largemouth bass.

Identification. Body elongate. More than 55 scales in lateral line. Deep notch between spiny and soft dorsal. Second-to-last spine less than half the length of the longest. Dark blotches on side usually form a broad horizontal band (may be faint or absent). Dorsal spines 10. Anal spines 3. End of jaw usually extends beyond rear edge of eye in adults. Typically dark olive green on back fading to brassy green on sides and cream-colored on belly. Horizontal band fully formed on juveniles. Tails of juveniles often reddish with a dark vertical band and a transparent margin.

Markings tend to be more bold on younger largemouth bass, such as on this 7-inch sub-adult.

Size. Commonly 6 to 18 inches. State survey max. size 23.2 inches. Conn. State Record 12.9 pounds. Max. reported size for northern strain largemouth bass 15.5 pounds, 28 inches.

Distribution. Native to the eastern half of the United States excluding most of the Eastern Seaboard states. Successfully introduced throughout the United States, Mexico, extreme southern Canada and many other parts of the world. Largemouth bass may be the most widely distributed fish species in Connecticut and are present in almost all water bodies, where they are typically common to abundant.

All maps created in 2009. See CT DEEP Fish Community Data for updated distributions.

Habits. Can thrive in a variety of habitats, but prefer lakes and ponds or backwaters of streams and rivers with at least moderate amounts of vegetation. Males can readily be observed guarding their nests (which appear on the bottom as circular light-colored areas about 18 inches in diameter) during May and June in shallow shoal areas. Largemouth bass can be caught by angling with a variety of baits and lures. They are easy to keep in home aquariums, but grow large and are aggressive. They will eat dry pellets, but need at least some live or fresh food to thrive. Largemouth bass typically stay in the center of the water column and will chase (or eat) smaller fishes.

An aquarium shot of a 2.7-inch juvenile largemouth bass.

Comments. The most popular gamefish in the country, the largemouth bass is also the principal predator in most of our state’s lakes and ponds and thus plays a key role in the health of aquatic ecosystems. The Massachusetts State Record (15.5 pounds) is the largest northern strain largemouth bass on record. Florida strain largemouths can exceed 20 pounds. 

Occasionally, largemouth bass are very pale, lacking any significant blotches and/or the trademark dark horizontal band.

Text and images adapted from Jacobs, R. P., O'Donnell, E. B., and Connecticut DEEP. (2009). A Pictorial Guide to Freshwater Fishes of Connecticut. Hartford, CT. Available for purchase at the DEEP Store.