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populations became established and evolved in these waters as a result of natural phenomena that occured over an extended period of time. Within a very short time following colonization of the Bonneville Basin, cutthroat populations began to decline drastically. As early as 1872, declines of the cutthroat trout in Utah lakes were observed (Yarrow 1874). Decline in lake populations was associated with similar reductions in stream populations. Losses of native trout were related to overharvest by commercial fishing and loss of habitat resulting from diversion and dewatering of area streams-used for spawning and rearing. Another event which undoubtedly had a major impact on Bonneville cutthroat was introduction ofnon-native salmonids such as rainbow trout. Hybridization that resulted, virtually eliminated the genotypic characters of native cutthroat populations and replaced them with hybrids exhibiting cutthroat-rainbow characteristics. Influences on native cutthroat trout proceeded at a very rapid rate and by the early 1900's, S. c. utah was believed to be extinct. Under the assumption that the Bonneville cutthroat was extinct, state managers of sport fisheries utilized cutthroat trout from Yellowstone Lake. Management of Utah waters with the Yellowstone Lake strain still continues today. Recently, several populations of what appear to be pure S. c. utah have been identified in small isolated streams in Utah, Nevada and Wyoming. These populations can be used for evaluating the potential role of native cutthroat trout in present and future sport fishery management. As indicated by Behnke (1976c), the idea of supporting angling for a rare or unique trout while trying to increase their abundance may appear contradictory to management goals. However, to increase abundance of a rare or unique trout, it will be necessary to re-establish the fish in waters within its native range. Such introductions would include public fishing waters. Behnke noted that no trout species has become rare or endangered through excessive sport fishing. There is, however, evidence that cutthroat trout populations can be suppressed, thus requiring special regulations for protection. Studies indicate increased abundance, size and an- gling rate for cutthroat following initiation of specialized regulations (Bjornn 1975; Bjornn and Thurow 1974; Hogander et al. 1974). Bonneville cutthroat populations would increase numerically from specific programs and would provide a real benefit to sport fishery management. Pres- entpopulations are confined to small isolated streams which are poor or margi- nal trout habitat. Although these fish are restricted to poor waters, Bonneville cutthroat appear to be in a healthy biological condition. Substitute fisheries perhaps can be established in other waters in Utah. An increase in fishable waters will be needed as the angling population increases and there is more competition for use of the aquatic resource. A second benefit to sport fishery management could be the piscivorous food habits of native cutthroat. Historically, the Utah cutthroat and the Lahontan cutthroat trout were known to be piscivorous in their feeding habits. In docu- menting the effects of the Newlands Project on the Pyramid Lake fishery, Behnke (1974) stated that the official record of Lahontan cutthroat was 12.7 kg (411bs) but that other reliable statements revealed that a fish of 19.2 kg (621bs) was taken from Pyramid Lake, Nevada, in 1916. Behnke reported that the Lahontan cutthroat trout fed extensively on tui chub (Gila bicolor). The cut- throat from Utah Lake also reached large sizes. These fish were probably old since the fishery was unexploited at that time and were large because of their piscivorous feeding habits. The present management of cutthroat trout fisheries utilize the Yellowstone Lake form which is not known to be piscivorous. Cutthroat trout in Yellowstone Lake occur together ecologically [summer water temperatures rarely get above 15.5°C (60°F)] with fish that could be used as forage such as red-side shiner and longnose sucker (Catostomus catostomus) but• do not feed upon them. Yel- lowstone Lake cutthroat reached a length of about 477 mm (18 inches) at the end of their seventh growing season (Carlander 1969). In contrast, cutthroat trout in 20