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Nose Current Velocity The probability-of-use curve for nose velocity developed for Sheep Creek is shown in Figure 1. The optimum was 2.0 ft/sec. The Green River nose velocity probability-of-use curve had an optimum of 2.4 ft/sec (Figure 2). The proportion of available and used habitat observed in each velocity is given for Sheep Creek (Figure 3). The majority of available habitat was greater then 2.6 ft/see, while the kokanee had positive selectivity values between 1.41-2.80 ft/sec. The opposite situation occurs in the Green River (Figure 4). The majority of available habitat was at nose velocities between 1.81 and 3.00 ft/sec. ~ The Sheep Creek depth probability-of-use curve (Figure 5) shows an optimum of 0.8 ft. A similar curve with a deeper optimum, 1.1 feet, occurred in the Green River (Figure 6). The frequency histogram for depth in Sheep Creek indicated a scarcity of available habitat deeper than 1.6 feet (Figure 7). Kokanee seem to be using the habitat in proportion to its availability, with positive selectivity occurring between 0.61-1.40 feet. In the Green River available habitat was fairly constant across all depth intervals (Figure 8). Positive selection was found between 0.61-1.60 feet. Substrate Probability-of-use curves for substrate in Sheep Creek (Figure 9) and the Green River (FigurelO) were both centered around class 5.0 which represents gravel. Available substrate in Sheep Creek (Figure 11) was dominated by class 4.7, which represents 70% gravel and 30% sand, and class 6.0 or rubble. Sand was abundant in the rubble dominated areas as well, but this classification cannot show this. Virtually all Sheep Creek redds were found in areas with a 4.7 value substrate. In the Green River (Figure 12), available habitat was dominated by gravel, rubble, and gravel-rubble combinations. A total of 88% of redds were located in gravel. DISCUSSION Probability-of-use curves for kokanee spawning have been published (Bovee 1978). Data came from kokanee spawning streams in Washington (Hunger 1973). Comparison of the IFG curves from Bovee (1978) to those in this paper showed differences. The IFG velocity curve (Figure 2) showed an optimum of 0.6-0.8 ft/sec, maximum 2.7 ft/sec. This is different from both the Sheep Creek (Figure 1) and the Green River (Figure 2) curves. The IFG depth curve (Figure 14) had a shallower optimum and maximum value than either the Sheep Creek (Figure 5) or Green River (Figure 6) curves. The IFG substrate curve (Figure 15)- was similar to both substrate curves developed in this paper (Figures 9 and 10). The minor differences between the Sheep Creek and Green River curves can be explained by the abundance of sand in Sheep Creek. 26