Survival and Abundance of Introduced Fishes near San Antonio, Texas

Introduced fishes comprise a substantial fraction of the fish fauna in 2 Bexar County waters: 35% in upper San Antonio River and 43% in Braunig Reservoir. Four species (Astyanax mexicanus, Poecilia latipinna, P. formosa, and Cichlasoma cyanoguttatum) are south Texas fishes displaced northward. Two species (Cyprinodon variegatus and Menidia beryllina) are recent introductions from estuarine waters. Four species (Hypostomus plecostomus, Poecilia reticulata, Sarotherodon mossambicus, and S. aureus) are exotics from South America, the Lesser Antilles, Africa, and Israel, respectively. Although P. reticulata is now added to the Texas fish fauna the apparent disappearance of another exotic, Belonesox belezanus, leaves the number of exotic poeciliids in Texas unchanged. The abundance of exotics is of substantial concern and care should be exercised to reduce the possibility of additional escapes.