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• Lengths, weights, and coefficients of condition of captured fish <br /> with lengths exceeding 100 mm are presented in Table 7. Based on <br /> information summarized by Carlaader (1969), suckers and whitefish. were <br /> in good condition. No seasonal or upstream versus downstream <br /> differences in coefficients of condition were apparent is the study. <br /> The results of the surveys indicated that several species seem to <br /> move to different areas is the river during the year. During high water <br /> and relatively fast flows characteristic of the spring and early summer, <br /> white suckers, speckled dace, and redside shiners occurred predominantly <br /> among rocks situated in the mid-portion of the river. However, during <br /> low-flow conditions in the summer and fall, fish were largely confined <br /> to rip-rap areas above the silo. Surveys conducted is September and <br /> November also revealed no flannelmouth suckers, or large-sized whitefish <br /> or white suckers. Ia addition, the presence of young-of-the-year brown <br /> [rout and whitefish, suggested Chat this segment of the river is used <br /> for spawning. <br /> In summary, the Williams Fork River just above the confluence with <br /> the Yampa River supports a fishery dominated by speckled dace, redside <br /> shiners, mottled sculpin, and white suckers, listed in decreasing order <br /> of numerical abundance. Gamefish such as brown [rout, whitefish, and <br /> rainbow trout are present but occur in low numbers. The river <br /> represents marginal habitat for gamefish with minimal cover consisting <br /> of submerged boulders. Rip-rap areas above the silo represent important <br /> habitat, particularly during Low-water conditions. <br /> 3.4 Potential Effects of HiainR Operations <br /> Ecological studies which have addressed the impacts of mining <br /> activities oa aquatic ecosystems in the West are few. Although adverse <br /> impacts have been associated with mining acitivites in numerous <br /> drainages of the eastern United States, minimal problems have been <br /> iadeatified in the few studies in western states. The primary cause of <br /> problems in eastern streams is lowered pH, ferric hydroxide <br /> precipitation, and heavy metals associated with the acid mine drainage. <br />• These changes have lowered macroiavertebrate density and diversity and <br /> eliminated fish species from streams (Vaughan et a1. 1978). <br /> <br />11 <br />