(weight in grains) x( 100, 000) 



K = 



3 

 (length in mm) 



Macrohabitat parameters were quantified in areas where 

 relatively high numbers of YOY grayling were captured (referred 

 to as "intensive-use areas" by Skaar (1989)) to characterize the 

 general habitat the YOY grayling were using. Four locations were 

 selected as macrohabitat areas on the lower section of the east 

 channel of the Big Hole River (section G) where large numbers of 

 YOY grayling were captured. Transects were established 

 perpendicular to the direction of flow and were spaced from five 

 to 2 feet apart. Depth, velocity, substrate, and cover were 

 quantified at 1.0 foot intervals along each transect except in 

 some isolated backwaters where measurements were taken every 3 . 

 feet. Depths were measured to the nearest 0.1 foot with a yard 

 stick affixed to a wooden handle and velocities were taken at 0.6 

 total depth using a type AA flow meter (Price model) and rod. 

 Substrate composition was visually established using the standard 

 size categories of silt (<0.0024 in.), sand (0.0024-0.0787 in.), 

 small gravel (0.0787-0.236 in.), large gravel (0.236-2.52 in.), 

 and cobble (2.52-9.84 in.). No boulders (>9.84 in.) were found 

 in measured areas. Embeddedness was also visually estimated by 

 examining cobbles and large gravel particles at each increment of 

 the transect for the percentage of the particle that was embedded 

 in the fines. Cover types were characterized, if present, at 

 each point along the transect as aquatic vegetation, terrestrial 

 vegetation, soil clump (from eroding streambanks) , pool (over 2.0 

 feet deep) , bank, and debris. 



Microhabitat measurements were taken from one hour to two 

 weeks following capture under flow conditions that were not 

 different by more than 20%. The area inside of a 3.28 square 

 foot area centered on the capture site was quantified with 

 respect to depth, velocity (at 0.6 depth and bottom), substrate, 



10 



