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(Escalante Desertl and a~~•~aak.~ ~4%ali~~:- ',~:_inages which flowed into I ~::~~ ::~:r~~ neville but became ,closed basins -~sll~ ,~. ~ ~g desiccation of the lake. The decline in ezumbers caf won-~ev_~_ie cutthroat trout following ontx~y of pioneer settlers into the basr~-~ was very marked and rapid (Yarrow 1374; Saior 1884; Woodruffe 1892) Initial decline in once abundant populations resulted from overharvest. ~ his was particularly true of lake populations which received heavy pressure from commercial fishing. Trout was a highly prized food source by early settlers and miners in Utah and this readily available local market created heavy pressure on trout populations in the area It was estimated that an average daily seine haul from Utah Lake was 68 kg (150 lbs) for summer periods and 18 kg (401bs) durinn the winter (Yarrow 1874). During the Wheeler expedition of 1872, Dr_ Yarrow interviewed a Mr. Madsen who had been fishing Utah Lake commercially since 1854. Mr. Madsen indicated that his harvest, had been decreasing annually because of increased commercial fishing. Some early laws were enacted to provide protection to fish popularions, but because of the lack of enforcement, greedy individuals continued to overharvest lake populations of S. c. utah. The conclusions drawn by Dr. Yarrow (1-8 74) was well stated: "In conclusion, it may be stated that the Utah Lake trout is of vast economic importance to the settlers of the Ureat Salt Lake VaIIey, supplying as it does a comparatively cheap and most excellent article of sustenance, and one to the preservation of which special attention should be speedily give~~i, since, if means are not shortly taken to prevent the destructive methods of fishing now employed the species must become extinct after a few years." Loss of habitat also hastened the decline of cutthroat populations. Ursder the leadership of Brigham Young, Mormon pioneer leader, settlements were established throughout the Bonneville Basin. Water became a prerequisite to settlement and most basin streams were altered by water diversions to meet culinary and irrigation needs. Many miles of streams inhabited by Bonneville cutthroat were impacted dy colonization of the basin. The final event which drastically influenced S. c. utah was introduction of rainbow trout (Salm.e ga~~rdneri) in 1883 and other nonresident trout forms into Utah waters (Sigler and Miller 1963). These introductions and the hybridiza- tion that resulted, greatly irl~uenced genotypical and morphological charac- teristics of native cutthroat trout in Utah. It was evident that within 100 years following settlement of the Bonneville Basin, native trout had been reduced to a point where many writers believed that S. c. utah was extinct (Miller 1950; Cope 1955; Sigler and Miller 1963}. Present There is recent evidence that remnant populations of S. c. utah still exist in a few isolated streams within Nevada, Utah and Wyoming (Behnke 1970, 1973a, 1973b, 1975a, 1975b, 1976a, and 1976b). In all cases, these remaining popula- tions are confined to small streams with limited habitat (Table 2J. In spite of the environmental extremes, S, c, Utah still existbut their numbers and growth are suppressed by marginal habitat conditions. The survival of present native cutthroat populations that thrive even under adverse environmental conditions illustrates the adaptive ability of this subspecies to exist under wide variety of habitat conditions. TAXONOMIC DESCRIPTION Early efforts to describe native trout in Utah were frustrated by the lack of diagnostic criteria for comparisons and the amount of hybridization that had resulted from introduction of other subspecies of cutthroat and rainbow trout (Tanner and Hayes 1933; Behnke 1976a). Tanner and Hayes stated, "The exact identity of the trout in this state as they existed when the first explorers entered