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Bonneville Basin -_ ~~, - _ ~ ~t~:re includes alI cutthroat trout z s ~ ~ncf~ <br />species (Salmo cL ; ~ ~ ~ -, ~, _„~~ r,~ing distinguished by major +9ra;ix~ages <br />or geographical a ~-a~ f ~~e, ctxe name S. c. Utah has been used to ,iesignatc <br />those native trout found ir, tie ~'svnnevsile Basin. <br />Even more troul:~lesome than difference in nomenclature is the lack of unique <br />diagnostic characters upon whi<;h positive identification can be based (Behnke <br />1970; Behnke 1976a}. A review of museum specimens collected from the Salt <br />Lake and Utah Lake drainages (1872-1915) has provided certain taxonomic <br />differences upon which to base classification. Behnke stressed that these dif- <br />ferences are based on comparison of anticipated mean values of certa;.n charac- <br />ters. Furthermore, it was also stressed that much overlap occurs in many <br />taxonomic characters of interior forms of cutthroat trout. <br />Biochemical analysis, using electrophoreticpatteins has also proven to be of <br />little value in providing conclusive differences in several groups of cutthroat <br />and rainbow trout (Stalnaker et al. 1975; Wydoski et al. 1976). These workers <br />did locate an unusual variation in lactate dehydrogenase (LDH) in samples of <br />Bonneville Basin cutthroat from the Deep Creek Mountains. This variation <br />suggested that some unique event(s) caused a variant allele to occur in cutthroat <br />trout of the Snake Valley area. Snake ~~alley cutthroat were also differentiated <br />from other Bonneville Basin cutthroat populations by having mare basibx-an- <br />chialteeth, alonger head, a deeper more compressed body and a longer dorsal fin <br />positioned more posteriorly (Hickman 1977). Hickman further discussed <br />taxonomy of existing Bonneville cattlxroat populations through use oFprincipal <br />component, discriminate, and Wilks and Lambda analyses. From examination <br />of 16 characters, 13ickman determined that basibranchial teeth, pyloric caeca, <br />scales in the lateral line series, cundal peduncle depth, and gillrakers provided <br />the best discriminating power i'or differentiating between cutthroat populati ens <br />(Table 3). <br />These findings indicated that cutthroat populations on the western boundary <br />of the basin were most divergent from populations located in the no;°theastern <br />area. In addition, there was considerably more overlap in populations from the <br />central and southern portions of the Bonneville Basin (Hickman 197'7). Graphi- <br />cal representation of Hickman's data provides a better comparison o1~ character <br />divergence in $onneville cutthroat populations (Figures 2 and 3). <br />To summarize the diagnostic characteristics for S. c. Utah, the following mean <br />values should be used for comparison: Vertebrae, 61-62; gillrakers, 18-20; <br />pyloric caeca, 30-40; scales above lateral line, 36-42; scales in lateral series, <br />155-179; and basibranchial teeth present in at least 90 percent of populations <br />(Behnke 1976a). The spotting pattern is also slightly different from other <br />subspecies of cutthroat trout; the spots are larger and fewer but more evenly <br />distributed over the entire body in S. c. utah. <br />BIOLO(aY AND LIFE HISTORY <br />Food Habits <br />Information on food habits of S. c. Utah is very limited. Buckley (1874) briefly <br />mentioned food found in cutthroat taken from the Weber River. All stomachs <br />examined by Buckley contained terrestrial insects such as wasps, beetles and <br />ants. Yarrow (1874) described food preferences of cutthroat trout in 1Jtah Lake. <br />Cutthroat in this large limnetic environment were very non-selective and <br />consumed both terrestrial and aquatic food items such as invertebrates, snakes, <br />frogs, and small fish. The piscivorous aspects of lake populations of Bonneville <br />cutthroat were particularly interesting. Yarrow (1874) stated, "The trout is <br />