Smallmouth Bass (Micropterus dolomieu)

(c) MN DNR, C. Iverson

Fish of the Mississippi River

Introduction

Smallmouth bass thrive here in the Mississippi National River and Recreation Area. Its population upstream of the Coon Rapids Dam supports a world-renowned fishery. This native of the upper and middle Mississippi River basin has been introduced widely throughout North America and now lives in all major drainages in Minnesota.

People have been instrumental in maintaining the smallmouth bass’s stable population. They have expanded the smallmouth’s range by stocking them in lakes and rivers to create new fishing opportunities. In recent years, they have improved water quality in the Mississippi River and stabilized the river bank with rock, which creates preferred bass habitat. But today, people may also be harming smallmouth bass and other Mississippi River fish through human medications that end up in lakes and rivers. Residues of these human drugs can lead to reproductive mutations in aquatic organisms.

The smallmouth bass’s popularity with anglers stems from its aggressive disposition, powerful runs, and acrobatic leaps and somersaults when hooked. Smallmouth bass eat small fish, crayfish, insects and frogs. It prefers clear water with rocky bottoms and builds and defends both its spawning nests and young from predators until they are large enough to fend for themselves.

Fascinating Facts

• Bass are a member of the sunfish family.
• The smallmouth bass received its scientific name by mistake. The museum specimen used to assign its genus name Micropterus had a torn dorsal fin, creating the misconception that the fish had a small fin following the dorsal fin. Micropterus is Greek for "small fin."

Identification

Key ID Features: Red eyes and a large mouth that does not extend beyond those eyes distinguish a smallmouth bass from its relative, the largemouth bass. Dark wavy lines extend back from the eye and its stocky body often has dark vertical bands. Smallmouth bass vary in color from mottled dark green to bronze or pale gold, depending on the water in which they swim. An average smallmouth weighs 1-4 pounds and is about 12-21 inches in length.

Present in Park: Common in the northern reaches of the park and futher north.

Habitat: Rocky bottomed streams and lakes. Prefers clean, cold water.

MN Status: Sport fish

For Further Reading

Encyclopedia of Life. 2017.” Micropterus dolomieu – Bass.” Accessed May 3. http://eol.org/pages/207898/overview

Minnesota Department of Natural Resources. 2017. “Bass.” Accessed May 3. http://www.dnr.state.mn.us/fish/bass/index.html