Lepomis macrochirus
bluegill

This species is native to lakes and streams in the St. Lawrence, Great Lakes, and Mississippi River systems.

Thus, it ranges from Quebec to northern Mexico. However, it has been introduced widely in places such as Hawaii, Africa, Asia, South America, and Europe. (Froese, Pauly, and eds., 2002; Murdy, Baker, and Musick, 1997)

Bluegill prefer to live in lakes and slow-moving, rocky streams. They can often be found in deep beds of weeds. In Hawaii they primarily inhabit reservoirs. Though they are freshwater fish, they can tolerate salinities up to 18% and are present in tributaries of the Chesapeake Bay. (Froese, Pauly, and eds., 2002; Murdy, Baker, and Musick, 1997)

Like other sunfish, bluegill have very deep and highly compressed bodies. In other words, they are "tall" and "flat." They have a small mouth on a short head. The dorsal fin is continuous, with the front part spiny and the back part soft and round with a dark smudge at the base. The tail fin is slightly forked but rounded. The body is mainly olive green with yellowish underneath. Their name "bluegill" comes from the iridescent blue and purple region on the cheek and gill cover (opercle). A close look reveals six to eight olive-colored vertical bars on the sides.

Typically, adults are between 10 and 15 cm but they can grow as large as 41 cm.

Young bluegill are a paler version of the adults, usually silver with a slight purple sheen. (Froese, Pauly, and eds., 2002; Murdy, Baker, and Musick, 1997; Williams, 1996)

Bluegill typically live 4 to 6 years but can reach 8 to 11 years old in captivity. (Froese, Pauly, and eds., 2002; Williams, 1996)

Bluegill are most active at dawn. During the day they stay hidden under cover, and they move to shallow water to spend the night. Schools may contain 10 to 20 fish. (Williams, 1996)

Home Range

Home ranges of bluegill are less than 30 square meters. (Williams, 1996)

Males change color during breeding season so it seems likely that visual cues are important either to other males or to females. Grunting is involved in courtship.

The very small mouth of this fish is an adaptation to eating small animals. Bluegills are carnivores, primarily eating invertebrates such as snails, worms, shrimp, aquatic insects, small crayfish, and zooplankton. They can also consume small fish such as minnows and plant material such as algae. Young bluegill eat worms and zooplankton, staying under cover while adults feed more in the open. (Froese, Pauly, and eds., 2002; Murdy, Baker, and Musick, 1997; Williams, 1996)

Bluegill travel in schools and come into shallow water only at night. During the day they try to remain hidden. (Williams, 1996)

Bluegill are an important prey species for larger fish predators. They also impact insect populations by eating aquatic larvae.

Several countries where this species has been introduced report that it causes ecological problems. Bluegill overcrowd and stunt the growth of other fish and may even be responsible for causing extinction of a native fish in Panama. It is considered a pest in its introduced range. (Froese, Pauly, and eds., 2002)

This is an important game fish in the United States. Bluegill are fairly easy to catch and are good to eat. They are also used to stock rivers and lakes with food for largemouth bass, another important game fish. (Conservation Commission of Missouri, 2002; Williams, 1996)

Bluegill are abundant in their native range. Many individuals are raised in aquaculture facilities and used to stock waterways. (Conservation Commission of Missouri, 2002; Williams, 1996)