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distributed to Dexter NFHTC and Arizona's Bubbling Ponds SFH for grow out to 300 mm. Fish are then PIT tagged and repatriated to Lake Mohave. At the onset of the restoration program for RBS, management biologists recommended the development and maintenance of unique genetic reserve populations endemic to targeted drainages. The strategy was to preserve the genetic uniqueness of the stocks, each of which may have evolved novel adaptations to local environments. Since the turn of the century and extirpation of most of the wild populations in the Upper Colorado River mainstem, San Juan mainstem, and Lake Powell, and the decline of the middle Green River population, the primary source for genetic material needed to recover the species throughout the Colorado River basin has become the Lake Mohave stock. Some geneticists believe that Lake Mohave RBS contain all the available genetic diversity from inundated populations above the dam. Dowling and Minckley (1993) reported a continuum of mtDNA haplotypes from the upper Colorado down to Lake Mohave with an increase in genetic diversity from 0 in the upper Colorado River to 0.98 in Lake Mohave. Undesignated Tributary Systems Although the Recovery Goals (U.S. Fish & Wildlife Service 2002) do not identify goals specific to tributaries of the Lower Basin recovery unit, stocking RBS will establish new populations and increase chances for recovery. These tributaries are the Gila, Salt/Verde, Little Colorado, and the Bill Williams river systems. Natural populations of RBS were extirpated from the Gila River basin and lower Colorado River by 1960 (Hendrickson 1994). Minckley (1973) indicated the last known collection of RBS from the Verde River occurred in 1954 at Pecks Lake and from the lowermost reservoir of the Salt River (Saguaro Lake) in 1949. In 1980, the Service and the Arizona Department of Game and Fish signed an agreement to cooperatively reintroduce the species into the Gila River Basin. 11