How to Identify Bluegill

To identify Bluegill (Lepomis macrochirus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Highly variable depending on age, sex, and habitat. Generally, the back is olive-green to dark blue, fading to lighter green or yellow on the sides, and a yellow to orange or white belly. Males often display a bright orange or reddish-orange breast during spawning. Seven to eight dark, vertical bars are usually present on the sides, though these can be faint. A prominent dark spot is present at the posterior base of the dorsal fin. The opercular flap (ear flap) is black with no distinct margin.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Small mouth, not extending past the front of the eye., Long, pointed pectoral fins., Prominent black opercular flap (ear flap) without a colored margin., Dark spot at the posterior base of the dorsal fin., Often exhibits 7-8 faint vertical bars on the sides.

Dorsal fin

Single dorsal fin, deeply notched, with 10-11 spines in the anterior (spiny) portion and 10-12 soft rays in the posterior portion.

Tail fin

Slightly forked caudal fin.

Pectoral fin

Long and pointed, typically extending past the eye when bent forward.

Distinctive fins

Pelvic fins are thoracic, located directly below the pectoral fins. Anal fin has 3 spines and 10-12 soft rays.

Identification Tips

1. 1

   Opercular Flap (Ear Flap)

   Look for a solid black opercular flap without any colored margin. This is a key distinguishing feature from many other sunfish.

2. 2

   Pectoral Fins

   Observe the pectoral fins; they are typically long and pointed, often extending past the eye when pressed forward.

3. 3

   Mouth Size

   Note the relatively small mouth, which does not extend beyond the front of the eye.

4. 4

   Dorsal Fin Spot

   A distinct dark spot is usually present at the posterior base of the spiny dorsal fin.

5. 5

   Body Coloration and Bars

   While variable, the presence of 7-8 faint vertical bars on the sides, combined with the overall blue-green to yellow coloration and often an orange breast (especially in males), is indicative.

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