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<br />lacustrine environment with greatly altered streamflows and temperature <br />regimes. Associated with these habitat changes, some endemic Colorado River <br />fishes declined dramatically in the lower basin. Few studies on the biology or <br />ecological requirements of the fish were made in the lower basin but their <br />decline was documented by Miller (1961), Minckley and Deacon (1968), and <br />others. The rare fishes, however, were still found in the upper basin because <br />the system was altered much later in the 1960s versus 1930s in the lower basin. <br /> <br />In the 1960s, the competition for water resources of the upper basin <br />became more apparent and various reports were written to summarize the supply <br />and demand of water, or considered choices in the use of water from the <br />Colorado River (U.S. Water Resources Council 1968; National Research Council <br />1968). For a number of reasons including the demand for energy resources, a <br />comprehensive study was completed in 1971 that provided appraisals of natural <br />resources and their geographic distribution, made projections of future <br />requirements, defined problems and needs, apd presented a program with <br />alternatives for resource development and conservation to the year 2020 (U.S. <br />Water Resources Council 1971). This study stated that ample resources were <br />available to meet fishing and hunting needs on the upper basin if minimum <br />streamflows and adequate reservoir conservation pools were provided. It also <br />pointed out that the recreational capacity for fishing and hunting could be <br />increased if adequate conservation measures were taken to protect and enhance <br />key fish and wildlife habitat. However, the report also stated that the water <br />surface needed to meet the recreation generated by nonresidents would not be <br />adequate by the year 2020. The report did not include conservation of the rare <br />fishes because their status was not fully known at that time. <br /> <br />6 <br />