The San Bernardino Valley, on the West side of the Malpai region, is the northern   tip of the watershed for the Rio Yaqui, a river which flows for 300 miles south from here to its mouth on the Gulf of California. The species of fish found in the Rio Yaqui are different from any found in other rivers in the United States. The short stretch of perennial flow in Black Draw, on the San Bernardino National Wildlife Refuge, is the only natural habitat for these fish in the U.S. The refuge was established specifically to protect habitat for these fish. As it turned out, several other rare species that are dependant on aquatic habitat, such as Chiricahua leopard frog, Mexican garter snake, and Huachuca water umbel, are also found there. Populations of Rio Yaqui fish have been impacted by a number of factors in Mexico, including dam building, introduction of non-native fish, and water diversion. Non-native fish that have been introduced for sportfishing have been especially harmful, because they are aggressive predators which have decimated several native species along the main stem of the river. The best surviving populations of Rio Yaqui fish are in small, somewhat isolated tributaries, such as Black Draw and Cajon Bonito, where the exotic predatory species have not gotten   established. Because of severe declines in their populations, many of the Rio   Yaqui fish are listed as Threatened or Endangered. The species are the Yaqui   chub, Yaqui catfish, Yaqui topminnow, Mexican stoneroller, Yaqui sucker, and   beautiful shiner. The best opportunity to protect these species is in the   small tributaries, which can be managed more easily than highly modified   stretches of the main stem of the Rio Yaqui. The Malpai Group works closely   with the U.S. Fish and Wildlife Service in several ways to improve habitat   conditions for these fish. The most extensive project that will benefit these   fish is our watershed improvement work, in which we are building many small   erosion control structures along the numerous arroyos that feed into Black   Draw. This is a cost-share project with USFWS and BLM which is intended to   slow erosion and catch sediment, so that more vegetation can grow along these   drainages. This will also benefit downstream aquatic habitat by reducing   siltation and moderating flood flows that come from these watersheds. We are   also coordinating with USFWS on fire planning in the San Bernardino Valley   through the Habitat Conservation Plan process, which is intended to improve   vegetation cover of perennial grass, which will in turn improve watershed   function through reduced erosion and increased water infiltration.