TN00206 BLUEGILL LEPOMIS MACROCHIRUS
Physical description: This is a barred or plain-sided sunfish with a short dark-margined earflap and a black spot in the rear of the soft dorsal fin. The adults are usually from 80-220 mm TL. The body is deep and very compressed and the dorsal profile of the head is straight or slightly convex with the nape bulging in large males. The mouth is small, terminal and oblique and the eye is large. The earflap is round or oval and not long. The dorsal fin is moderately emarginate at the junction of the spinous and soft portions. The caudal fin is emarginate with the lobes rounded. The pelvic fin has a filamentous extension of the largest ray. The pectoral is elongate and pointed *4205*. The lateral line is usually complete. The body is slab sided and deep, with the dorsal profile more curved than ventral, becoming steep in adults. The mouth is small, and oblique, with the maxillary scarcely reaching the eye. The opercular flap is rounded posteriorly, and long in audlts, with the membranous margin of the narrow caudal fin emarginate. Dorsal fin X, is 10-12. Anal fin III, 10-12. The gill rakers are long and slender, and there are no palatine teeth. The pharyngeal bones are moderately stout with sharp slender teeth *1178,789*. There are (38)41-46(50) lateral line scales with 7-8(9) scales above the lateral line and (14)15-16(17) scales below the lateral line. There are (18)19-20(21) circumpeduncle scales, (910(12) doesal spines, (9)10-11(13) dorsal rays, and 3 anal spines. There are (9)11-12 anal rays and (12)13-14(15) pectoral rays *4205*. There are many anterior scales above the lateral line with black centers. The male does not have a small swollen ring around the urogenital pore *1178,789*. The juveniles are lighter in color than the adults, usually silvery, sometimes with a purplish sheen, and no blue sreaks on lower sides of the head *1641*. The unfertilized eggs are pale yellow, with an average diameter of 1.04 mm. They are adhesive, with a large oil globule at the polar end. The fertilized eggs are amber, 1.2-1.4 mm in diameter, noticeably thick and laminated, not always round prior to water hardening. The adhesiveness is variable *1641*. The nuptial male has a dorsum and upper midside that is pale blue, blue-olive, or blue-green. Some fish have a violet iridescence and the bars when present are medium to dark olive. The head is medium to dark olive and the lower midside and venter are about the same shade as the dorsum, or brassy to russet. The head is medium to dark olive and the cheek and opercle have a lime-green to blue iridescence. The lower jaw and ventral margin of the gill cover are pale blue to turquoise, and the iris is copper to red. The earflap is black. The median fins are medium to dark olive with black blotches or streaks. The pelvic fin is dusky or black and the pectoral fin is pale yellow-olive. Adult females and juveniles are largely olive, with purple and/or yellow sheens on the body. Reproduction: This species is mature at ages 1-2 with an average life span of 4-6, although as many as 11 years *4205*. Bluegills are repeat spawners and may spawn throughout the spring and summer when water temperatures are between 17-31 degrees C with peak spawning at water temperatures of 24-27 degrees C *2107*. Egg incubation ranges from 1.5-5 days *2107*. Fecundity increases with the size and age of the female, and ranges from 2540-64000 eggs per female with an average of 18,300. The number of larvae per nest ranges from 4670-224900 and averages 17914-86631 per nest *1641*. This species is a colonia nester in groups of up to 50 *1203*. The male escavates the nest by undulating the caudal peduncle fromn side to side while in a verical position *1200*. The nest diameter is highly variable (15-91 cm) and the depth from the rim to the base varies from 1.3-15 cm *1641*. They may spawn in the nests of other centrarchids *1641,1200*. The male produces courtship calls (grunts) *1200*. When the female enters the nest, both adults swim about the nest in a circular path, and eventuallly rest with the male upright and the female at a angle with their bellies touching. A few eggs and milt are released and the behavior is repeated *1200*. The female does not deposit all of the eggs in 1 nest, nor is one nest used by only one female *1200*. Behavior: This species travels in a loose school of 10-20, and is most active at dawn. They remain near cover during the day, and disperse into shallows at night *1200*. They winter in deeper waters, and winter aggregations break up at 10 degrees. The males move inshore before the females, and some individuals move up into sluggish streams or into channels in the spring *1641*. The home range does not exceed 28 meters of stream *1641*. Homing was exhibited in 60% of the larger fish, from distances up to 0.67 km when displaced *1641,1200*. The male defends the nest territory before and after spawning against all species, but most vigously against other male sunfishes *1200*. The most aggressive behavior is the frontal threat display. Lateral displays occur commonly *1200*. Grazing fish sight feed, frequently eating insects that fall on the surface of the water. It often hunts individual larvae or plankton. It feeds largely on plankton in limnetic the zone during the day, and moves to the littoral zone at dusk to feed on benthic organisms and organisms attached to/or living on plants *1641,1200*. Feeding decreases at water temperatures below 10-12.8 degrees *1200*. Prior to the free swim- ming stage, larvae periodically make vertical migrations to the surface. They may hide in vegetation or become concentrated in shallow coves after leaving the nest. Lake populations typically move offshore to the limnetic zone *1641*. Juveniles move in schools, particualry at sizes greater than 14.4 mm. They initially inhabit the limnetic zone (upper 3.5 m), then return to the littoral zone after 3-4 weeks, at a length of from 20-25 mm. They remain near shore during the winter and larger juveniles make diurnal inshore-offshore movements *1641*. Origin: This species is native in the Tennessee, Big Sandy and Peedee drainages in Virginia *4205*. Population parameters: The mortality rate of groups over age III-IV is 57-99%. Aquatic/terrestrial associations: This species is associated with Ambloplites rupestris, Centrarchus macropterus, Enneacanthus gloriosus, Micropterus salmoides, Pomoxis nigromaculatus, Catostomus commersoni, Campostoma anomalum, Rhinichthys cataractae, Semotilus atromaculatus, Pimephales notatus, Notropis cornutus, N. rubellus, Notruus flavus, Etheostoma nigrum, E. flabellare, M. dolomieui and L. cyanellus *1178,1200*. It hybridizes with other Lepomis, rock bass, flier, largemouth bass and black crappie *1178*. Bluegill and largemouth bass have been managed as an important prey-predator combination because of its excellance as a sport and food fish *1583,1584,1177*. POPULATION PARAMETERS: IN CORDELL HULL RESERVOIR TOTAL LENGTHS AT SUCCESSIVE ANNULI WERE 72, 107, 130, 142, AND 148 MM *TN5319*, IN NICKAJACK RESERVOIR, TOTAL LENGTHS AT SUCCESSIVE ANNULI WERE 58, 92, 124, 145, AND 167 MM *TN5391*, IN EASTERN TVA RESERVOIRS, TOTAL LENGTHS AT SUCCESSIVE ANNULI AVERAGED 53, 94, 127, 157, AND 188 MM *TN5393*, ANNULUS FORMATION COMPLETE BY LATE APRIL-EARLY MAY IN CENTER HILL RESERVOIR AND BY LATE MAY-EARLY JUNE IN BURGESS FALLS LAKE *TN5392*
| Life History |
References for Life History Codes
2107, 1178, 816, 1203, 1641, 1200, 849, 789, 1583, 1584, 1177, 4205, TN5319, TN5391, TN5392, TN5335
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