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Archive - March 2019

bluegill Lepomis macrochirus

What is a Bluegill?
A bluegill is a type of fish. Fishes are aquatic animals that have a backbone. Their body temperature varies with that of the environment. Some fishes are covered entirely or partially with scales. They reproduce by laying eggs. Fishes breathe through gills. Many fishes have a streamlined shape for quick movement in water. They do not have limbs with fingers or toes. 

What Does It Look Like? 
The bluegill’s body is flattened side to side. Its back and sides are green while the belly is yellow to white. Sometimes dark bars can be seen on the sides. A dark flap extends from its gill cover. Its pectoral fins are long and pointed. There are three, hard spines in its anal fin. A black spot is present at the rear of each the dorsal and anal fins. The male becomes brightly colored when mating, with a blue head and back, red-orange breast and belly and black pelvic fins.  

How Big is It?
The average size for a bluegill in Illinois is one-fourth pound in weight and eight to 10 inches long. The current state record for a bluegill caught by hook and line is three pounds eight ounces.

Where Does It Live?
The bluegill lives statewide in lakes, ponds, rivers, swamps and creeks that have warm, clear water and many aquatic plants. 

How Does It Reproduce?
Bluegill are mature at one year of age. They reproduce, or “spawn,” from May through August. The male builds a nest by fanning his fins over the bottom of the water body he lives in, making a depression. The female then deposits from 2,300 to 67,000 eggs. More than one female may lay eggs in the same nest, and each female may deposit eggs in more than one nest. The male releases sperm over the eggs to fertilize them. The male stays with the nest to guard it. The fertilized eggs hatch in five to 10 days.

What Does It Eat?
This species eats insects, small fishes, crayfish, snails and other small aquatic animals.

Does Anything Eat It?
Many species feed on bluegills and their eggs. Aquatic turtles, snakes, other fishes, American bullfrogs (Lithobates catesbeianus), birds, mammals and aquatic insect immature stages (such as dragonfly nymphs) eat bluegills.

What Else Should I Know About It?
The bluegill is Illinois’ State Fish.

It has a life span of five to six years.

Bluegills swim in groups of 20 to 30 individuals. They are most active in the evening and early morning.

Small, male bluegills that cannot establish their own territory may spawn by sneaking into the territory of a larger male while he is not watching, then releasing their sperm over the eggs. These small, male bluegills may also behave like female bluegills and enter the guarded nest in that manner, too. 

Can I Fish for It?
Yes. The bluegill is a sport fish in Illinois. It may be fished for legally by following all relevant laws and regulations. See the latest edition of the Illinois Fishing Guide published by the Illinois Department of Natural Resources for details.

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