The largemouth bass is a freshwater fish found in U.S. lakes and slow rivers, with a large jaw that reaches behind the eye in adults. The closely related Florida bass (Micropterus salmoides) looks nearly identical, so a genetic test is needed to tell them apart reliably.
Appearance
- Appearance
- Adults show a dark stripe along the side and a jaw that reaches behind the eye.
Look-alikes
Florida bass and largemouth bass look so alike that a photo cannot separate them reliably. A genetic test is needed for a sure answer.
Why they get mixed upBoth have a large jaw and a dark side stripe.
With the mouth closed, the jaw of a spotted bass (Micropterus punctulatus) does not extend beyond the back edge of the eye. A largemouth jaw reaches well behind it.
Why they get mixed upBoth can show a dark side stripe.
The jaw of a smallmouth bass (Micropterus dolomieu) stops before the eye’s back edge, and its sides often show vertical bars rather than one clear dark stripe.
| Jaw past eye | Side pattern | Photo ID | |
|---|---|---|---|
| Largemouth bass | Yes | Dark horizontal stripe | Not reliable vs Florida bass |
| Florida bass | Yes | Similar dark stripe | Genetic test needed |
| Spotted bass | No | Broken stripe and belly spots | Side and jaw can help |
| Smallmouth bass | No | Often vertical bars | Side and jaw can help |
Where it lives
- Typical habitats
- Lakes
- Slow rivers
- Vegetated shallows
- Range
- Native across much of the central and eastern United States and stocked well beyond that range.
- When it’s recorded
Recorded year-round, every year · most records in May–Aug
20,691 observations in the US · 10 years · for reference
Behavior
- Diet
- Adults eat fish, crayfish, and other large animals without backbones that live in water.
- Activity
- They often wait near plants or submerged wood before striking prey.
Life cycle
- Breeding season
- In Minnesota, males begin nesting in May or June.
- Nest
- Males make nests in quiet shallow water and guard eggs and newly hatched young.
Name and classification
- About the name
- Older guides called the largemouth bass Micropterus salmoides.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
Culture and stories
- Culture and stories
- A favorite sport fish in many U.S. lakes.
16 sources
- iNaturalist taxon API
- Florida FWC bass name change
- Texas Parks Black Bass ID
- 環境省 特定外来生物一覧
- 環境省 オオクチバス
- 환경부 큰입배스 산란
- Minnesota DNR Largemouth Bass
- Florida FWC Florida Bass
- NIES black bass species in Japan
- Korean largemouth bass genetic origin study
- Jeonbuk invasive fish spawning months
- Florida FWC bass genetics
- USGS Bluegill species profile
- Texas Parks Bluegill
- 법제처 생태계교란 생물의 지정과 국내 피해사례
- NIES older broad-concept OOkuchibasu