Southern Conchos Trout
Oncorhynchus sp. nov.
There appear to be no immediate threats to the existing population, as it is remote and not easily accessible. Limitations to range expansion include overgrazing by livestock and the effects of logging and road building in this sub-basin.
Mexican native trout (in Spanish "Truchas Mexicanas")—Mexican rainbow trout, sometimes Baja rainbow trout (Oncorhynchus mykiss nelsoni) and Mexican golden trout (Oncorhynchus chrysogaster) occur in the Pacific ocean tributaries of the Baja California peninsula and in the Sierra Madre Occidental of northwest Mexico as far south as Victoria de Durango in the state of Durango. Many forms of the Mexican rainbow trout (Oncorhynchus mykiss nelsoni and O. m. ssp.), subspecies of the rainbow trout, have been described. The Mexican golden trout (Oncorhynchus chrysogaster) is a recognized species.
The phylogeny of Mexican native trout is an unsettled science. Some studies suggest that the trout are descendants of the coastal rainbow trout (O. m. irideus) based on the idea that in wetter times, rainbow trout (steelhead) could have easily gained access to Baja California and Sierra Madre Occidental tributaries from the Pacific ocean. Others have suggested a connection to the inland redband trout (O. m. gairdneri). Others have pointed to evidence in some populations that Mexican native trouts may have descended from cutthroat trout.