As is expectable in a desert, the fish fauna tends to be widely scattered geographically, with low biodiversity. Most of the fish fauna is restricted to the Rio Grande, Rio Pecos, and Rio Conchos along with some tributaries that have permanent or semipermanent water. Springs are the other resource for fish faunas. Both river and spring resources have been reduced because of drought, increased irrigation farming, and development, such as for SPAs. Edwards et al. (2002:130) note that "Clark Hubbs observed that the Río Sauz went dry in 1947 and no surface waters were available in the river valley (in Miller, 1961). Additionally, at least 30 springs have gone dry in Chihuahua and Coahuila and river discharges of the Río Nazas, Bolson Mayrán, Río Aguanaval, Bolson Viesca, Río de Nadadores, Río Saltillo, Río Salinas, Río del Carmen and the middle Rio Grande are reduced (Contreras-Balderas and Lozano-Vilano, 1994)". Cuatro Ciénegas, as might be expected, has a number of endemic fish (probably 10 of 17 species of Cuatro Ciénegas fishes).
A checklist of the fishes of the Rio Grande drainage, Doña Ana, El Paso, and Hudspeth counties is available.
Last Update: 26 Jun 2006