STUDY AREA 



The upper Big Hole River is characterized by numerous 

 tributary streams and braided channels. Common fish species 

 include Arctic grayling ( Thymallus arcticus ) , brook trout 

 ( Salvelinus fontinalis ) , burbot ( Lota lota ) , white sucker 

 ( Catostomus commersoni ) , longnose sucker (C. catostomus ) , mottled 

 sculpin (Cottus bairdi ) , and longnose dace ( Rhinichthys 

 cataractae ) . Rainbow trout ( Oncorhynchus mykiss ) and brown trout 

 ( Salmo trutta ) are less common in the upper portion of the 

 drainage than in the lower sections of the drainage (R. Oswald, 

 pers. comm. ) . 



Six grayling spawning sites (Figure 1) were identified by 

 MDFWP personnel during the spring spawning survey in 1990. The 

 presence of "bright" areas of substrate where the gravel had been 

 washed clean (Shepard and Oswald 1989) was often indicative of a 

 spawning site. Additional sites (Swamp Creek, Pintlar Creek, 

 etc.) were surveyed (electrof ished) on the advice of R. Oswald 

 (MDFWP) or because of observations made during the survey. 



Three irrigation ditches in the Wisdom area were also 

 surveyed. All three had been sampled at some time during the 

 previous two summers (Skaar 1988; McMichael 1989). Sampling 

 locations, distances, and dates are given in Table 1. 



