The smallmouth bass (Micropterus dolomieu) is a species of fish in the sunfish family (Centrarchidae). Other common names include smallie, bronzeback and brown bass. The smallmouth is the state fish of Tennessee.

Identification

The smallmouth bass is generally green with dark vertical bands rather than a horizontal band along the side. There are 13-15 soft rays in the dorsal fin, and the upper jaw never extends beyond the eye.

Distribution

Smallmouth originally ranged north into Minnesota and southern Quebec, south to the Tennessee River in Alabama and west to eastern Oklahoma and southwestern Arkansas. Today there are few states, east or west of the Rocky Mountains, where populations have not become established. Florida and Louisiana are apparently free of smallmouth bass.

Behavior

Smallmouth are generally more aggressive in nature than largemouth. This is due in part to their preference for current, which stimulates their metabolism and appetite. Males begin moving into spawning areas once the surface temperature reaches 50-plus degrees Fahrenheit. Nests are usually located near shore on pea-size gravel bottoms, rocky outcroppings on deep bluffs and downstream from boulders or some other obstruction that offers protection against strong current in streams. Males may spawn with several females on a single nest. Eggs hatch in about 10 days if water temperatures are in the mid-50s, but can hatch in 2-3 days if temperatures are in the mid-70s. Males guard the nest from the time eggs are laid until fry begin to disperse, a period of up to a month. As in other black bass, fry begin to feed on zooplankton, switching to insect larvae and finally fish and crayfish as they grow.

Diet

High on the list of forage for this predator fish are crawfish, which are commonly found in the aquatic food chain of fisheries with rock substrates. The smallmouth will also feed on insects and smaller fish. Juvenile smallmouth feed on zooplankton.

Habitat

Smallmouth are found in clearer water than the largemouth. Smallmouth relate to two types of habitat: moving water and rock. The fish is specially adapted to live in streams and rivers. The smallmouth prefers cooler water temperatures than the largemouth, although both species can be found living in the same fishery. Because it is relatively intolerant of pollution, the smallmouth bass is a good natural indicator of a healthy environment, though it can better adjust to changes in water condition than most trout species.