RESULTS AND DISCUSSION 



Distribution and Abundance of Fishes 



The highest concentrations of YOY Arctic grayling were 

 located in the east channel (Steel Creek channel) of the Big Hole 

 River below the town of Wisdom (section G; Table 2) . The highest 

 densities in this area occurred from the confluence of Steel 

 Creek downstream for approximately 2.5 miles. Notable 

 concentrations of YOY grayling were also found in the west 

 channel of the Big Hole River below Wisdom (section C) and in an 

 irrigation ditch on Cal Erb's (formerly McDowell's) ranch just 

 upstream from Wisdom (section J) . Relatively few YOY grayling 

 were captured on Swamp Creek (section B) , Steel Creek (section 

 I) , the Big Hole River upstream of Wisdom (section D) , and the 

 upper east channel of the Big Hole River below Wisdom (section 

 F) . Age 1+ Arctic grayling, though very sparse in general, were 

 most numerous in sections C and G, following a similar pattern of 

 distribution as that of the YOY grayling. No grayling and only 

 11 brook trout were captured in approximately 5.0 miles of river 

 between Pintlar Creek and Squaw Creek in an area that was 

 severely dewatered during the summer of 1988. 



Though not quantified in many cases, the higher densities of 

 YOY grayling were found in similar habitat, and in close 

 association, with YOY mountain whitefish indicating they may 

 exhibit similar habitat preferences during their first summer of 

 life. Young-of-the-year brook trout were most plentiful in Steel 

 Creek (section I) and in the lower section of Swamp Creek 

 (section B) . They were also relatively abundant in the lower 

 east channel of the Big Hole River (section G) , however the 

 linear densities should be interpreted cautiously as they include 

 multiple samplings in some circumstances which may give a 

 misleading impression overestimating the actual relative density 

 in a given section. 



Adult brook trout were most numerous in lower Swamp Creek 



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