Largemouth, Smallmouth or Spotted? Three Checks

The three black bass turn up in the same water, take the same lures, and are regulated differently often enough that it is worth being able to tell them apart while the fish is still in your hand.

Three checks, in order of how quickly they work.

1. The jaw

Close the fish's mouth and look at where the back corner of the upper jaw sits relative to the eye.

• Largemouth — the jaw extends clearly past the rear edge of the eye.
• Smallmouth — the jaw ends at or before the rear edge of the eye.
• Spotted — roughly level with the rear edge. In between, which is why the next two checks matter.

This is the fastest test and it settles largemouth against the other two immediately.

2. Stripe direction

• Largemouth — a ragged dark horizontal band running the length of the flank, breaking into blotches.
• Smallmouth — dark vertical bars, plus usually three bars radiating back from the eye.
• Spotted — a broken horizontal band, similar to a largemouth, plus the spot rows below.

Colour is a supporting hint rather than a test: smallmouth run bronze and brown-gold, largemouth run green. But water clarity changes both dramatically, so trust the pattern direction rather than the hue.

3. The tongue

This is the one that identifies a spotted bass definitively, and almost nobody does it.

Run a fingertip over the fish's tongue. A spotted bass has a rough patch of tiny teeth there. Largemouth and smallmouth are smooth.

Combine that with the rows of small dark spots below the lateral line — which neither of the others has — and the identification is certain.

Quick reference

Why bother

Because the rules differ, and often in the same water.

Many states set a separate minimum or slot limit for smallmouth. Several exclude spotted bass from the black bass limit entirely, and some actively encourage their removal where they hybridise with and displace native smallmouth. A few waters have species-specific catch-and-release seasons.

None of that is discoverable from the fish, so the check is worth the four seconds it takes — and if the two candidates on your list have different limits and you cannot separate them, the safe answer is to release it.

The other black bass you may meet

Three more turn up regionally and are worth knowing about, because several states manage them separately again:

All three are river fish with restricted ranges, and several are the focus of conservation programmes because they hybridise with introduced spotted bass.

Why colour is the wrong first check

Bass colour tracks water clarity rather than species. The same largemouth is dark olive in a stained pond and pale silvery-green in a clear reservoir, and a smallmouth from a tannic river can look almost black.

Which is why the jaw and the stripe direction come first. Both are structural, and neither changes with the water the fish came out of.