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for river water. The impact of reduced flows on fish and wildlife was evaluated, and flows to meet most production and survival needs for all sizes of trout and to ensure winter survival were recommended. Wiley and Mullan (1975) evaluated consequences of four flow regimes to help the public allocate their basic water supply. When discharges released from Fontenelle Reservoir resulted in excessive water velocities in relation to available shelter, low use, low yield, and modest standing crop of trout were realized (Mullan et aL 1976). Wiley and Dufek (1980) discussed standing stocks and mortality rates of rainbow and brown trout in the Fontenelle tail- water; growth was excellent because of the produc- tive environment. The main factor limiting standing stock was lack of instream cover. Early data col- lected after some instream cover (large boulders) was provided suggested increased stock in the im- proved areas. Gaufin et aL (1960) conducted an aquatic survey of the Green River and its tributaries in the Flaming Gorge Reservoir Basin. A checklist of native and in- troduced fishes was included in their report. In early September 1962, prior to the closure of Flaming Gorge Dam, the Green River and its tributaries for 362 km above the damsite were treated with rotenone to cause a large-scale reduc- tion of "coarse" fish populations and allow reser- voirs and rivers to realize their full potential as trout fisheries (Dexter 1965). The result of introduc- tion of rotenone into the complex river ecosystem was a biological catastrophe. However, Dexter reported a gradual increase in river biota, aided by the stocking of "desired" fish species, by the time his paper was written. Binns (1967) substantiated Dexter's report and discussed devastation of the in- vertebrate community and its subsequent inability to recover. Vanicek et aL (1970) analyzed the effect on the Green River in Utah of the closure in November 1962 of Flaming Gorge Dam. They studied changes in the river environment; determined species com- position, distribution, and abundance of fishes; and compared 1963-1966 distribution of fishes with preimpoundment collections. Seasonal flows changed from high spring and low winter flows to a relatively stabilized seasonal flow pattern, and temperatures and temperature fluctuations decreased. Native fish populations were replaced by rainbow trout in a 42-km section below the damsite. Stalnaker and Holden (1973) stated that no native species were reproducing in the 105-km area from the dam to the mouth of the Yampa River and that trout had replaced native species to the confluence of the Yampa. Four native species (humpback chub, Colorado squawfish, bonytail chub, and razorback sucker) were considered rare. These authors sug- gested that the Yampa River, the Green and Col- orado rivers in the Canyonlands section of southeastern Utah, and Desolation Canyon on the middle Green River appeared to be the only areas in this sub-basin ecologically suitable for maintaining reproducing populations of the large-river endemic fishes. The tailwater fishery of Flaming Gorge Reservoir had discharge and shelter components that resulted in an exceptional trout yield prior to dysfunction by lowered water temperatures (Mullan et aL 1976). In 1978, the U.S. Bureau of Reclamation installed an in- let modification to aid the failing tailwater trout fishery. Warmer water drawn from higher reservoir levels to enhance trout production has elevated stream temperatures and may restore successful reproduction of Colorado squawfish below the dam (Holden 1979). Miller (1965) discussed the fishes of Dinosaur Na- tional Monument and reviewed changes resulting from the closure of Flaming Gorge Dam. Seethaler et aL (1979) reviewed earlier work and emphasized the importance of waters in Dinosaur National Monument for the continued existence of endemic fishes. They listed stream alteration (due to dams, irrigation, dewatering, channelization, and unstable banks), increases in competition and predation (due to introduction of non-native fishes), pollution, eutrophication, and other factors as possible causes of declines of endangered and threatened endemic fishes. Three sampling areas of Holden and Stalnaker (1975a) were on the Green River below its con- fluence with the Yampa. Flannelmouth and bluehead suckers were predominant in this area. Joseph et aL (1977) stressed the importance of the Yampa River for maintenance of Green River spawning temperatures; recent evidence demon- strates that the Yampa itself provides spawning habitat for rare native fishes. An extensive review of the literature on fishes of the Yampa was done by Carlson et aL (1979). Holden and Stalnaker (1975b) concluded that the Yampa River was of extreme im- portance to the preservation of rare and endangered fishes in the Colorado River Basin; all of the rare forms were then present in the Yampa, and some were apparently reproducing. Carlson et aL (1979) presented data on fishes collected in the Yampa River from 1975 to 1978 between Lily Park Pool near Cross Mountain and Hayden, Colorado. Fish distribution, relative abundance, reproduction, growth, food, and habitat were discussed. In 1981, Tyus et aL (1982) discovered the first spawning ground of Colorado squawfish in lower Yampa Can- yon. Radiotelemetered fish moved into this location from the upper Yampa and middle Green rivers. This discovery links the decline of the Colorado squawfish with blockage of spawning migrations. Joseph et aL (1977) reviewed the history of the White River Basin and stated that changes in the White River due to potential oil shale development will significantly affect the Green River. Carlson et aL (1979) provided an extensive literature review on the White River fishes and a report on fishes col- lected in Colorado from 1975 to 1978. Lanigan and Berry (1979) provided an in-depth report on the endemic fishes of the White River in Utah. 4