Mountain whitefish appeared to grow more rapidly than 

 either grayling or brook trout between July 6 and 24, after which 

 grayling grew more rapidly and surpassed whitefish in mean TL. 

 Young-of-the-year brook trout grew relatively slowly and showed a 

 greater variation (some very small age 1+ may have erroneously 

 been included in the calculation of YOY mean TL) . Skaar (1989) 

 reported very similar growth rates for both Arctic grayling and 

 brook trout in these waters during the summer of 1988. 



Condition factors (K) were calculated for 46 age 1+ Arctic 

 grayling captured during July and August, 1989 in the study area 

 for comparison with the condition factors reported for the same 

 waters by Liknes (1981) for 1979 and by Skaar (1989) for 1988. 

 For grayling between 6.4 and 13 inches TL the mean K value (+SD) 

 was 1.10 (±.20). This was higher (the fish were in better 

 condition) than those measured by either Liknes (1981) [K=0.95 

 +.08] or Skaar (1989) [K=1.06 +.11]. Flows were slightly higher 

 and temperatures were slightly cooler during the summer of 1989 

 than they were during the same period of 1988 which may help 

 explain the healthier individual fish. One could also speculate 

 that with the much reduced densities of age 1+ grayling since 

 1979, the grayling that survive to age I have considerably less 

 competition for food and space, if food and space are limiting. 



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

 Macrohabitat Utilization 



The east channel of the Big Hole River (section G) was 

 chosen for habitat measurements due to the high densities of YOY 

 Arctic grayling found there. Four areas were intensively 

 measured with respect to depth, velocity, substrate, and cover to 

 develop an index of availability for these parameters in an 

 attempt to determine whether YOY grayling were selecting habitat 

 types in proportion to their occurrence. 



Seventeen YOY grayling were captured in macrohabitat area 1 

 (Fig. 3) which was located approximately 200 feet upstream of the 

 'intensive-use area C described in Skaar (1989) and was in an 



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