Douglas High School Pond. Photo by Marty Underwood, 2/17/2009, Douglas, Arizona

The Yaqui chub (Gila purpurea) and the Yaqui topminnow (Poeciliopsis occidentalis sonoriensis) are Federally-listed species found only in the drainage of the Rio Yaqui, which drains portions of Southwestern New Mexico, Northwestern Chihuahua, Mexico, Southeastern Arizona and Northeastern Sonora, Mexico. Loss of habitat, due to agricultural practices, is the main reason for the listing of these two fish. These species were generally found in river, stream, or spring habitats and they had the ability to move up or downstream depending on conditions, but because of the loss of habitat, artificial impoundments have been created in the region to provide refuge for these fish. These impoundments, while not native habitat, do provide the necessary requirements for survivorship and productivity for these species. In addition, the habitat and water that feeds the impoundments can be managed more easily. However, one of the drawbacks to this type of management is the loss of genetic diversity due to restricted populations. Because of the likely loss of genetic diversity it was deemed beneficial by Refuge Staff to transfer fish between San Bernardino National Wildlife Refuge and the Douglas High School Pond.