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4443 Decomposition of organic matter on the lake bottom during late summer has not resulted in oxygen depletion, which is a critical factor in fish survival. Measurements of pH show the water in Ruedi Reservoir to range between 7.0 and 7.5, or near neutral, which is characteristic of most high country waters. . (10) New food organisms for trout in Ruedi Reservoir and in the Fryingpan River downstream have become available with establishment of the reservoir. According to the Colorado Division of Wildlife, zooplankton (cladocerous and copepods), a different type of food organism common to lakes, have invaded and become fairly well established in Ruedi Reservoir. Analysis of fish growth patterns shows a tremendous increase in growth rate during the year &uedi Reservoir first filled and for possibly one year following. Since then, growth rate has leveled off and gener~ly deteriorated. Many of the trout examined in 1971 were in quite poor physical condi- tion. This may, in part, be due to a failure of lake type bottom food organisms to become established in the reservoir. Electrofishing and netting samples show both western white and long-nosed suckers to be quite numerous. They may be an indication of an expanding population and could present a more serious problem with the food supply in years to come. (11) Ruedi Reservoir could become one of the more productive of the fluctuating mountain reservoirs in Colorado providing that establishment of bottom organisms and/or opossum shrimp takes place within the next few years and the rough fish population does not go unchecked (Colorado Division of Wildlife, 1972). . I (12) Cooler summer flows in the Fryingpan River below Rue~i Reservoir have helped increase the reproduction of stone- flies, mayflies, and caddis flies, all part of the fish food chain. Yearly "die off" of aquatic life in Ruedi Reservoir has been washed downstream increasing the availability of food supplies for trout. Some buildup of algae has occurred in the river just below the dam. Insects such as mosquitoes, gnats, and flies may be increased due to ponded water in Ruedi Reservoir following drawdown and because of the increased water surface. (13) Overburden was removed in areas immediately downstream from the outlet works, exposing about 6 acres of gravel which UOw s~rve as a brown trout spawning area. Studies presently underway by the Colorado Division of Wildlife IV-53 .