Head to head
Guadalupe Bass vs Smallmouth Bass
A Guadalupe bass and a smallmouth bass are both flowing-water specialists among the black bass, but one is found naturally nowhere outside a handful of central Texas rivers while the other ranges across a huge swath of North America, and where the two now meet the encounter is not a good one for the rarer species.
| Guadalupe Bass | Smallmouth Bass | |
|---|---|---|
| Scientific name | Micropterus treculii | Micropterus dolomieu |
| Natural range | A handful of central Texas rivers | Eastern and central North America |
| Conservation status | Vulnerable | Least Concern |
| Main threat | Hybridisation with introduced smallmouth bass | None significant |
| Habitat | Flowing, rocky rivers | Cooler, clearer rivers and rocky lakes |
| Relative size | Smaller, more streamlined | Larger |
| State symbol status | Official state fish of Texas | None |
| Diet | Insects, crayfish, small fish | Crayfish, insects, smaller fish |
Guadalupe Bass vs Smallmouth Bass: common questions
Why is the Guadalupe bass threatened by the smallmouth bass?
Smallmouth bass introduced into the Guadalupe bass's naturally limited central Texas rivers can interbreed with it, and because the Guadalupe bass's entire natural population is confined to just a handful of river systems, this hybridisation can gradually dilute the genetic distinctiveness of pure Guadalupe bass populations across a meaningful share of the species' total range, a threat the far more widespread smallmouth bass has no equivalent version of anywhere in its own range.
How can you tell a Guadalupe bass from a smallmouth bass?
The Guadalupe bass is generally smaller and more streamlined and is found only within its narrow central Texas range, while the smallmouth bass is somewhat larger, has an upper jaw ending roughly beneath the eye, and occurs across a vastly broader native and introduced range spanning much of North America, differences that combined with location usually settle the identification.
Do the Guadalupe bass and smallmouth bass prefer the same kind of water?
Yes, both species favour cooler, clearer, rockier flowing water with moderate current over the warmer, weedier, more still water other black bass species tolerate well, a shared habitat preference that is exactly what allows the two species to come into contact and hybridise where smallmouth bass have been introduced into Guadalupe bass rivers.