The Rio Fuerte drains 33,835 km2.of the Sierra Madre Occidental of the Mexican states of Chihuahua, Sinaloa, Durango, and Sonora. Its tributaries pass through Barranca del Cobre (Copper Canyon) as they drop from headwaters as high as 2,808 m above sea level to the Mar de Cortes (Gulf of California). Its headwaters interdigitate closely with east-flowing tributaries of the Rio Conchos, an important tributary of the Rio Bravo (Grande), and interior drainages of Chihuahua and Durango, such as the Rio Nazas. The Fuerte shares its fish fauna with these neighboring drainages, and has no endemics. Northernmost tributaries are relatively arid, but southern tributaries drain sub-tropical areas with much higher rainfall. Dams and diversions now block movements of many marine fish species that used to move far upstream, and more are in construction or planned. Large river fish habitats at lower elevations have been converted almost entirely into canals and the natural mainstream channel now carries only minimal or highly modified discharges, often contaminated by agricultural runoff. At higher elevations, fish habitats have been severely impacted by logging and grazing. Logging development continues, recently expanding from traditional conifers to lower-elevation oaks. Exotic fishes have had, or surely will have, broad impacts on the native fauna through predation, competition and hybridization. Tilapias from Africa are widely established now, as are several centrarchids that will undoubtedly impact on the native cichlid (Cichlasoma beani), cyprinids, catostomids, poeciliids, and others. While not well studied taxonomically, the basin's native catfish, closely related to Ictalurus pricei, is now broadly hybridizing with introduced channel catfish (I. punctatus). At higher elevations, the beautiful native Mexican golden trout is very likely to hybridize with rainbow trout being widely introduced for fish culture. El Rio Fuerte drena 33,835 km2 de la Sierra Madre Occidental en los estados de Chihuahua, Sinaloa, Durango y Sonora. Sus tributarios fluyen a traves de la Barranca de! Cobre (Copper Canyon) y caen desde las cabeceras de 2,808 m sobre el nivel del mar hacia el Mar de Cortes (Gulf of California). Sus cabeceras interdigitan cercanamente con los tributarios de flujo este del Rio Conchos, un importante tributario del Rio Bravo (Grande) y drenajes interiores de Chihuahua y Durango como el Rio Nazas. El Fuerte comparte su fauna de peces con estos drenajes vecinos y no presenta endemicos. Los tributarios norteños son relativamente aridos, pero los tributarios sureños drenan areas subtropicales con mayor regimen de lluvias. Las presas y canales, que bloquean ahora el movimiento de muchas especies de peces marinos que lo usaban para remontar el rio, siguen en construcción y planeación. Los habitats de peces de rios grandes en bajas elevaciones han sido convertidos en canales y el canal principal natural ahora mantiene descargas minimas o altamente modificadas, frecuentemente contaminadas por desechos de la agricultura. A grandes elevaciones, los habitat de los peces han sido impactados severamente por la tala y el pastoreo. Los desarrollo madereros continuan y recientemente se han expandido de las tradicionales coniferas a los encinos de mas baja elevaci6n. Los peces exóticos tienen o seguramente tendran grandes impactos sobre los peces nativos a traves de la depredación, competencia e hibridación. Las tilapias de Africa estan ahora ampliamente establecidas al igual que varios centrarquidos, que indudablemente impactan sobre el ciclido nativo (Cich/asona beani), ciprinidos, catost6midos, pecilidos y otros. Aunque no esta bien estudiado taxonomicamente, el bagre nativo de la cuenca, cercanamente relacionado a Ictalurus pricei, esta ahora hibridizandose ampliamente con el bagre de canal introducido. A grandes elevaciones, la hermosa trucha dorada Mexicana nativa, es muy posible que hibridice con la trucha arcoiris, que ha sido ampliamente introducida como pez de cultivo.

A grant has been awarded to Dr. Richard L. Mayden at Saint Louis University to conduct field and laboratory research in collaboration with other USA scientists and several scientists from Mexico on the environmental status, distribution, conservation and genetics of native trout populations of Mexico. While biologists have been aware of the existence of native trout in Mexico for over a century, they have received little study. Beginning in the mid-1990's a group of ichthyologists and conservation biologists from both Mexico and USA jointly formed an international alliance, Truchas Mexicanas, to better understand the native trout of the Sierra Madre Occidental. Through these efforts, scientists have discovered previously unknown trout species restricted to Mexico and introduced (non-native) populations of rainbow trout. The existence of these non-native rainbow trout originating from streams in the US and Canada in the ranges of the unique Mexican trout species is a significant threat to the future existence of native species. Rainbow trout are known to displace native trout species through competition or genetically "swamp out" their gene pools through aggressive hybridization. Other native populations of trout are also predicted to occur in the upper Rio Conchos; these populations are predicted to also be in danger from habitat destruction and introductions of rainbow trout. In this study we will inventory many river systems of the sierras for native and introduced trout species, including the upper Conchos River system. Genetic samples will be examined from all of these populations to evaluate genetic variability of native species and determine if any native populations are compromised genetically through hybridization with introduced rainbow trout. This research supports the development of an international alliance investigating native trout populations of Mexico and southwestern United States. Trout species are important game and forage species for human populations, constituting a major element of diets in some regions. Trout fisheries are also very important economic elements to some regions as trout are highly prized sport fish species. Understanding native trout species diversity in Mexico and its conservation and maintenance in these streams has a major impact on both fisheries and economic areas. Mexican trout species are the southern-most trout and are adapted to theses unique ecosystems. Introductions of non-native rainbow trouts will seriously jeopardize these adapted populations and lead to their extirpation from the region. This will have serious sociological and economic impacts for the native people of the region.

The mission of the Desert Fishes Council is to preserve the biological integrity of North America's desert aquatic ecosystems and their associated life forms, to hold symposia to report related research and management endeavors, and to effect rapid dissemination of information concerning activities of the Council and its members.