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(assignment of lengths to age groups was based on body 

 length-scale radius relationships derived by Liknes [1981]). The 

 relative abundance of the fish in the different size/age groups 

 was in stark contrast to that found by Liknes (1981) in two 

 sections in the Wisdom area in August 1978. The percentage of 

 fish in each of the size groups of 6.0-9.0, 9.0-11.0 and 11.0+ 

 inches was 18.3, 55.6, and 26.1, respectively. Comparable 

 percentages for fish found in the Wisdom area in 1988 (a subset 

 of data presented in Figure 4) were 65.6, 32.8 and 1.6, 

 apparently showing that age 1+ fish were relatively much more 

 abundant in 1988 than in 1978, and age 11+ and older fish were 

 relatively much less abundant. However, the ratios in 1988 may 

 be to some degree an artifact of the sampling techniques, which 

 were very inefficient at sampling many of the large pools that 

 were felt to be good habitat for large grayling. Furthermore, 

 the relative strength of the year classes could have been 

 different in 1978 than in 1988. 



Condition factors (K) were calculated for age 1+ and older 

 fish and compared to a similar analysis by Liknes (1981), who 

 collected fish in July and August from a section below the Wisdom 

 bridge. For fish between 6.9 and 12.4 inches, he calculated a 

 mean K value (+ SD) of 0.95 + 0.08. In this study, mean K values 

 (+ SD) for all age 1+ and older fish in the Study Area were 1.06 

 + 0.11. The relatively good condition of the fish in this study 

 was not expected. The high water temperatures and reduced space 

 caused by reduced discharge were anticipated to be stressful 

 factors that might contribute to poor condition. 



Habitat Utilization by Young-of-the-Year Arctic grayling 



Macrohabitat Utilization 



Swamp Creek (sample section J) and the oast channel of the 

 Big Hole River below the Wisdom bridge (sample section H) were 

 characterized for habitat use because they contained high 

 densities of YOY Arctic grayling (5 and 13 fish per 1000 ft, 

 respectively) . Some macrohabitat features of the two sample 

 sections were very similar, including discharge, gradient, 

 sinuosity, bank height and condition, and channel shape (Table 

 5) . Channel width and wetted stream width were somewhat greater 

 for the Big Hole River (72.3 ft and 18.0 ft, respectively) than 

 for Swamp Creek (60.2 ft and 14.8 ft, respectively). Arctic 

 grayling in both areas seemed to be orienting to the riffles. 

 For the Big Hole River and Swamp Creek, the YOY fish were 

 captured 2 3.9 ft and 27.2 ft, respectively, downstream from the 

 base of riffles and were in faster water — rapids, low-gradient 

 riffles or runs — at 84.4% and 74.1% of the capture sites, 

 respectively . 



