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inches, which corresponded to age 1+ and 11+ fish, respectively. 

 Fish over 6 inches had a mean (+ SD) condition factor (K) value 

 of 1.06 + 0.11, somewhat higher than the mean value of 0.95 + 

 0.08 calculated by Liknes (1981) for fish in the same general 

 area in 1979. 



Electrof ishing was used to characterize macro- and 

 microhabitat utilization by young-of-the-year Arctic grayling for 

 the east channel of the Big Hole River below the Wisdom bridge 

 and for Swamp Creek. Considering the two areas collectively, 

 fish were captured a mean distance of 24.9 ft downstream from the 

 base of riffles and were in fast water (rapids, low-gradient 

 riffles or runs) at 81% of the capture sites, and in slow water 

 (pools and slow runs) at 19% of the capture sites. Wetted stream 

 width at capture sites averaged 17.6 ft, while channel width 

 averaged 70.6 ft, and bank height averaged 2.5 ft. 



Young-of-the-year Arctic grayling were captured at depths 

 ranging from 0.2 to 3.0 ft in water with velocities ranging from 

 0.0 to 1.87 ft/s. Data on habitat availability were collected 

 only for areas near to capture sites, and an analysis of these 

 suggested that depths and velocities utilized by the fish were 

 limited relative to depths and velocities not used, and therefore 

 may have been selected preferentially. 



The types of substrate and percent of cover were estimated 

 for a 3.28 ft cell that was centered on the capture sites. 

 Substrate was divided into 6 types: silt, sand, small gravel, 

 large gravel, cobble and boulder, and all types except for 

 boulders were found at the capture sites. On the average no 

 substrate type predominated, and all types occupied between 15 

 and 26% of the cell. Cover, on the average, occupied 24% of the 

 cell. Aquatic vegetation was by far the most abundant type of 

 cover, and was found at 84.6% of the capture sites. 



Information about the movements of young-of-the-year Arctic 

 grayling in their first summer is largely circumstantial. A 

 separate study in April and May 1988 looked for the locations of 

 spawning Arctic grayling. Ripe or spent fish were found in many 

 locations that were in close proximity to areas where 

 concentrations of YOY fish were found in July and August. This 

 suggests that at least some fish stayed close to their natal 

 spawning gravels, but it cannot be ascertained if or how many 

 fish were more mobile and moved away from these areas. 



Site fidelity of young-of-the-year fish to riffles and runs 

 was observed in five areas that were electrof ished 14-29 days 

 after the initial electrof ishing survey. Forty-five YOY Arctic 

 grayling were captured in these areas during the initial survey, 

 while 3 3 were captured during the second survey. The fish were 

 not marked, so it is not known if they were the same fish that 



