The Guadalupe bass (Micropterus treculii) is found only in Texas and is the official state fish. This fish is endemic to the Edwards Plateau including the headwaters of the San Antonio River, and the Guadalupe River above Gonzales. Like other “black bass” including largemouth, smallmouth, and spotted bass, it is not a true bass at all but a member of the sunfish family (Centrarchidae). Some distinguishing features include; no vertical bars like smallmouth bass, jaw doesn’t extend beyond the eyes as in largemouth bass, and coloration extends lower on the body than in spotted bass (TPWD 2013).
The Guadalupe bass is found in fast, flowing water, whereas largemouth bass are found in quiet water. It does not grow to large size because they are adapted to small streams. Spawning begins in March with males building gravel nests for spawning, preferably in shallow water and having females lay their eggs.
Due to habitat changes, Guadalupe bass numbers have significantly declined in recent years. Since its evolutionary advantage was adapted to stronger stream flow rates this state fish is experiencing a disadvantage because of diminished flows causing a threat of hybridization with the introduced smallmouth bass.
Stocking of other game fish, such as small and largemouth, was introduced in 1974 to improve central Texas fishing. In the early 1990’s, TPWD began a pilot program to restock native Guadalupe bass in the attempts to outnumber the smallmouth-Guadalupe hybrid. Due to the success of the program further work is being done with fishermen to expand the program throughout the Hill Country (TPWD 2013).