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r 'c- I STUDY AREA < The White River arises in the Flattop Mountains of western Colorado and flows uninterrupted for 402 km before joining the Green River at Ouray, Utah. The study area (Figure 1) included 241 km of the White River and extended from the confluence of the White and Green rivers near Ouray, Utah to Rio Blanco Lake, an off- stream reservoir in Colorado. The White River rises from 1421 m above mean sea level (MSL) at its mouth to an elevation of 1723 m MSL at Rio Blanco Lake. The upper portion of the study area is bordered by agricultural land comprised of alfalfa fields, permanent pastures, and grain and corn crops. The lower portion is largely undeveloped, but some insults occur to the White River because of energy development, and several water development projects are planned. MATERIALS AND METHODS A standardized sampling program was developed. Five "homo- geneous" river sections 28-61 km in length were identified by evaluating the fishery habitat. These sections included canyons, low gradient braided sections and a high gradient, relatively clean water section. The five homogeneous sections (V, W, X, Y and Z) were treated as discrete strata (Figure 1), so that samples could be representative of all habitats and overall sampling variability would be reduced. Sampling procedures were similar to those presented by Archer et al. (1980). Sample sites within the stratum were selected by river miles from a table of random digits, for Strata V, W, X, Y and Z. All habitat types within a 0.8 km sample station were then sampled for 24 hours with trammel nets (46 x 1.8 m; 2.9 cm mesh, 25.4 cm wall), seines (4 m x 1.8 m; 6.3 mm mesh; double hung lead line), electrofishinggear (DC variable voltage pulsator with a 240 w generator) and wire traps (0.45 m diameter 0.77 m long, 25.4 rom mesh). After the 0.8 km station was sampled, electrofishing was continued downstream for 7.2 km. At that location a second station (0.8 km) was established, and all of the habitat types within the second 0.8 km were sampled for another 24 hours. An exception to the s~p1ing procedures was necessary for Stratum V since it was only 29 km in length. Electrofishing effort was reduced by one-half, and continued only 3.1 km downstream before the second 0.8 km section was sampled. Methods used in the radiotelemetry study of Colorado squaw- fish were presented in Tyus et al. (1981). The larval sampling procedures are given in the White River Report (Tyus and Harper 1982) but not repeated here since the data have not been completely analyzed. 42 ......