Smallmouth Bass

Micropterus dolomieu

smallmouth_bass_05-03-12.jpg

Image of smallmouth bass
Joseph R. Tomelleri. Used with permission.
Other Common Name
Brown Bass; Brownie; Bronzeback
Family

Centrarchidae (sunfishes) in the order Perciformes (perch-like fishes)

Description

The smallmouth bass is a large, elongated fish with a moderately large mouth. The cheek scales are much smaller than the rest of the body scales. The back and sides are greenish brown, with faint dark mottling and bars; the belly is whitish, overlain with dusky pigment.  There is no dark horizontal stripe, and it lacks rows of dark spots. In adults, the upper jaw reaches to about the rear margin of the eye. The tongue usually has a rough patch. The two dorsal fins are connected.

Similar species: The smallmouth bass is most closely related to the largemouth and spotted basses.

Key Identifiers
  • In adults, the upper jaw extends to about the rear margin of the eye; it does not extend beyond the back of the eye (in largemouth bass, the upper jaw extends far behind the back of the eye)
  • The 2 dorsal fins are connected
  • Side is plain, with a series of separate vertical bars
  • Very small cheek scales
Size

Total length: 10 to 20 inches; weight 1/2 to 4 pounds; maximum about 22 inches long and 6 pounds.

Smallmouth_Bass_Stonner_10-05-2014.jpg

Smallmouth bass being held up by a person
Smallmouth Bass
In smallmouth bass, the two dorsal fins are connected, the cheek scales are very small, and the upper jaw does not extend beyond the back of the eye.

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Three captured fish lying on a surface, left to right: largemouth bass, spotted bass, and smallmouth bass
Missouri's 3 Species of Black Basses: Largemouth, Spotted, and Smallmouth
From left to right: largemouth, spotted, and smallmouth bass. They are in the same genus, Micropterus, the "black basses."

smallmouth_bass.jpg

Image of a smallmouth bass
Smallmouth Bass
Habitat and conservation

Found predominantly in cool, clear Ozark streams and large reservoirs in the Ozarks. Found sparingly in the upper Mississippi River and its principal prairie tributaries that have clear water and permanent flow. Thrives in clear streams, with silt-free rock or gravel bottoms, near riffles but not in the main current. Although mostly found in streams in Missouri, it can be found in natural lakes and ponds in the northern parts of its North American range. Most active at dawn and dusk.

Foods

Carnivorous, feeding on fish, crayfish, and large aquatic insects.

image of Smallmouth Bass distribution map
Distribution in Missouri

Predominantly in cool, clear Ozark streams and large reservoirs in the Ozarks. Sparingly in the upper Mississippi River and most of its principal prairie tributaries.

Status

This is the most sought-after sport fish in the clear, cool streams of the central Ozarks. In recent years it has become increasingly abundant and important in the sport fishery of Table Rock Reservoir and Stockton Lake.

Life cycle

Individuals can live up to about 10 to 12 years. Populations have declined in the Moreau River drainage partly because of hybridization with an introduced population of the closely related spotted bass.

Human connections

A popular sport fish of the Ozarks. The most effective live baits include minnows, crayfish, and hellgrammites. Spinning and casting with the same types of lures used for taking largemouth bass also work. Some people consider fly fishing to be the ultimate sporting method for catching "brownies."

Ecosystem connections

In the Ozarks, the smallmouth bass is the dominant species of large, predatory fish in most streams. It is the ecological replacement, or counterpart, for the spotted bass and the largemouth bass in the clear, cool, permanent-flowing streams of the Ozarks.