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STUDY AREA Kokanee, the landlocked form of the sockeye salmon, was first stocked in Flaming Gorge Reservoir in 1963 (petengill et al. 1983). With the decline of the rainbow trout (Salmo gairdneri) fishery, due apparently to competition for zooplankton with kokanee, Utah chub (Gila atraria), and white sucker (Catostomous commersoni) (Schneidervin 1985), kokanee have become an important component of the sport fish harvest in Flaming Gorge Reservoir. Kokanee also serve as a forage species for large lake trout (Salvelinus namaycush) (Wengert 1985). Flaming Gorge Reservoir is located in Sweetwater County, southwest Wyoming and Daggett County, northeast Utah. Two major kokanee spawning streams to Flaming Gorge Reservoir are known--the Green River in Wyoming and Sheep Creek in Utah. The Green River spawning stock migrates 70 miles up the river as far as Fontenelle Dam. Substantial spawning takes place in the first 1.5 miles downstream from Fontenelle Dam. This stock spawns in late October and early November. Average discharge during this period in 1985 was 850 cfs. Sheep Creek enters Flaming Gorge in the canyon portion of the reservoir in Utah. Sheep Creek is a shallow, high gradient, canyon stream which has experienced two 100-year flood events recently; the first in July 1965 and the second in July 1985. This stock spawns in late August and September. Dishcharge averaged 55 cfs during this period in 1985. METHODS In both streams sP3:wning areas were located by sighting concentrations of kokanee. Precise locations were found by identifying the displaced gravel of the kokanee redds. Water depth, mean current velocity, and nose current velocity were measured immediately upstream from redds with a rod and Gurley current meter. Nose velocity was measured at 0.4 feet from the stream bottom (Smith 1973). Substrate was identified visually in the tailspill of all redds and placed in substrate class 1-8 according to Bovee and Cochnauer (1977). A vailab1e habitat was quantified by measuring the same parameters at 10 equally spaced stations along each of 211 transects in Sheep Creek and 66 transects in the Green River. A tape was used to locate the stations in Sheep Creek. This was not possible in the Green River, so a compass and trigonometry formulas were used. Probability-of-use curves were developed using frequency analysis following the methods described by Bovee and Cochnauer (1977). All results are given in English units because the IFIM is based on hydrologic concepts, and hydrologists use English units. RESULTS A total of 111 redds were measured in Sheep Creek and 323 in the Green River for probability-of-use curve construction. 25