Fish of the Mississippi River
The tap-tap of a bluegill nibbling bait dangled below a dock is many a child’s first fishing success. A member of the sunfish family, bluegills cruise warm, weedy water seeking insects, crustaceans, and zooplankton (microscopic water animals). Its acute daytime vision is great for finding food but it does not see well in low light. That makes it easy prey for large predators with good nighttime vision, such as walleyes.
Point to Ponder: What would happen with bluegill populations if water temperatures increase?
Unlike many fish, bluegills are streamlined side-to-side with a round, flat body averaging to 6-9 inches in length. In the spring, males excavate nests in coarse sand or gravel where they jealously guard their eggs and hatchlings until they disperse. While they are guarding the nests, bluegill populations can be overfished because of the concentration of fish and their aggressive attacks on anything that approaches their territory. Bluegill populations are also subject to “stunting,” a condition of too many tiny bluegills and an absence of large sunfish. The precise cause of this condition is unknown but fisheries managers employ various management approaches to correct it.
Key ID Features: The bluegill’s dark tip on its gill cover (commonly known as the ear flap) distinguishes it from other members of the sunfish family. It has an orange breast and a dark green back fading to silvery sides that have several dark vertical bars.
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Last updated: November 22, 2019