How to Identify Largemouth Bass

To identify Largemouth Bass (Micropterus salmoides), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Typically dark green to olive green on the back, fading to lighter green or golden on the sides, and white on the belly. A prominent, irregular horizontal dark stripe or series of blotches runs along the lateral line from the operculum to the caudal fin. Coloration can vary significantly based on habitat and water clarity.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Large mouth, with the upper jaw extending beyond the posterior margin of the eye when closed., Deeply notched dorsal fin, appearing almost as two separate fins., Lateral line often marked by a dark, irregular stripe or blotches., Scales on the cheek and operculum are smaller than those on the body.

Dorsal fin

Two dorsal fins, deeply notched, appearing almost separate. The anterior (spiny) dorsal fin has 9-11 spines, and the posterior (soft-rayed) dorsal fin has 12-14 soft rays.

Tail fin

Slightly forked caudal fin.

Pectoral fin

Paired pectoral fins, relatively small.

Distinctive fins

Pelvic fins are thoracic (located beneath or in front of the pectoral fins).

Identification Tips

1. 1

   Mouth Size

   The most definitive feature: the upper jaw (maxilla) extends beyond the posterior margin of the eye when the mouth is closed. This distinguishes it from the Smallmouth Bass.

2. 2

   Dorsal Fin

   The dorsal fin is deeply notched, almost appearing as two separate fins. The spiny and soft-rayed portions are clearly distinct.

3. 3

   Lateral Stripe

   A prominent, often broken or blotchy, dark horizontal stripe runs along the lateral line. This stripe can be very distinct or somewhat faded depending on the fish's environment.

4. 4

   Scales

   Scales on the cheek and operculum are noticeably smaller than the body scales.

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