The bluegill has 39 to 44 lateral line scales. Its dorsal fin contains nine to 11 spines and 10 to 12 soft rays, its anal fin three spines and 10 to 12 rays. The pectoral fin is long and pointed, extending past the eye when bent forward. The mouth is small; the upper jaw does not extend to the front of the eye. Always black, the flexible ear flap is small in juveniles, longer in adults. Juveniles and nonbreeding adults are light olive to gray on the back and sides with several evenly spaced, darker vertical bands. The venter varies from pale yellow to white. All but small individuals have a distinct black spot toward the rear of the soft dorsal fin. Breeding males darken, with the back and sides becoming purple.

Distribution

Bluegills appear to have been native to the eastern half of the United States, southeastern Canada and northeastern Mexico, exclusive of the coastal plain north of Virginia. Today, as a result of countless intentional as well as no doubt unintentional introductions, bluegill are found throughout the United States and northern Mexico.

Behavior

Bluegills begin spawning when water temperatures reach about 70°F. Spawning may peak in May or June, but continues until water temperatures cool in the fall. Because of their long spawning season, bluegills have very high reproductive potential, which often results in overpopulation in the face of low predation or low fishing pressure. Nests are created in shallow water, one to two feet in depth. Gravel substrate is preferred. Fifty or more nests may be crowded into a small area, thus creating a spawning bed. Males guard the nest until the eggs hatch and fry leave.

Diet

Young fish feed on plankton, but as they grow the diet shifts to aquatic insects and their larvae. Up to 50% of their diet may consist of midge larvae.

Habitat

The bluegill is a schooling fish with schools of 20–30 individuals. Bluegill seek the shade and cover of any variety of manmade cover, from boat docks to natural cover such as weedbeds, growing or submerged trees and underwater rock outcroppings and rockpiles.

Copyright May 14, 2008 by Craig Lamb