Bluegill
Lepomis macrochirus (Rafinesque)
Diagnosis.
The bluegill is a thin and much compressed sunfish, bluish or yellow-green,
with six to eight olive, chainlike, vertical bands down the sides (the
sides are unicolorous in large adults and fish from turbid water); a black
blotch in the posterior rays of the soft dorsal fin (in the adult); an
orange belly and bluish cheeks (in the adult male); a long and pointed
pectoral fin; a flexible and uniformly dark opercular flap; a small mouth
(the rear of the maxilla not reaching the front of the eye); and long,
thin gill rakers. The adult most closely resembles the redear sunfish
but differs in lacking red or orange on the opercular flap and in having
a black spot on the soft dorsal fin and long and thin gill rakers.
The young resembles the young orangespotted sunfish but has more numerous,
more regular, and narrower vertical bands. The baby bantam sunfish differs
from the baby bluegill in having an intense black spot on the soft dorsal
fin (not yet developed in baby bluegill) and in having a blackish head
and a more chubby body. The baby pumpkinseed has scattered dark spots
and flecks in the interspaces between the vertical bands. The baby warmouth
has a blackish head and face. Other Illinois sunfishes lack vertical bands
as juveniles. The species attains a length of about 310 mm (12 inches)
but is usually much smaller.
Variation.
For many years, three subspecies have been recognized: L. m. speciosus
in the Southwest, L. m. purpurescens in the Southeast, and L. m. macrochirus
from Lake Superior to the Gulf Coast. Bailey, Winn, & Smith (1954:139)
acknowledged that subspecies may be recognizable but recommended that
names be withheld until a thorough study of geographic variation in the
species had been made. In recent years much genetic mixing of local stocks
has occurred with the wholesale stocking of bluegills in reservoirs.
Ecology.
The bluegill reaches its greatest abundance in clear well-vegetated
lakes but also occurs in swamps, ponds, and in pools of streams of various
sizes, especially large rivers. Bluegill reach spawning age in from 2
to 3 years. Spawning occurs between April and September, starting when
the water reaches about 70°F.
Male bluegill build nests just prior to spawning activities in water
from 2 to 6 feet deep over sand or mud bottoms. Many bluegill build nests
in large groups along the shoreline which can easily be seen by anglers
in waters of moderate clarity. Females lay between 2,000 and 63,000 eggs
which hatch within 3 days following fertilization by males. Bluegill may
spawn several times and lay eggs in many nests. Males guard the nests
and protect the young until they reach about ½ inch. Young bluegill
travel in schools in deeper water and in aquatic vegetation to avoid predation
by other fish.
Bluegill eat a variety of small aquatic animals such as insects, crayfish,
small minnows, snails, and worms. Active bluegill feed at dusk and dawn.
Larger individuals move inshore at dawn and again at dusk to feed, while
remaining in deeper water either suspended or associated with weed edges
near deep water.
Distribution.
The bluegill is statewide and common, and there is no evidence that it
was ever any more so than at present.
Fishing For Bluegill.
(Spawning Time) As waters warm to near 70° F, bluegill
spawning activities begin in lakes and rivers. Adults can be observed
by fishermen boating or walking along shorelines while they make nests,
spawn, and guard the nest and young. Males react to invading live baits
and jigs presented near active nests by striking the bait. Once disturbed
while on the nests, bluegill only leave for a short time before returning
to resume spawning activities. Individuals not actively spawning can be
found resting in slightly deeper water near the spawning beds.
(Post spawning Time) Following the conclusion of spawning
activities, bluegill move to deeper water (suspending above the thermocline
from 10-18 feet deep) and in pockets of aquatic vegetation or other structural
features (wood or rocks) to avoid predation by other fish. The orientation
to water temperature gradients and physical structure (aquatic habitat)
provides the key to fishermen looking to catch this taste fish. Live baits
(such as crickets, nightcrawlers, worms, grubs) and small artificial baits
(such as jigs with twister tails and safety blade spinners ie. Beatle
spins) are effective ways to fish the target areas for catching slab bluegill.
Fish Species: Bluegill Document Date …. 06-07-2004
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