Summary 



A total of 39 sculpin ( Cottus ) samples were collected from waters 

 of the Kootenai National Forest in northwest Montana. Slimy 

 sculpin ( Cottus coqnatus ) were present in 16 of the collections. 

 Torrent sculpin ( Cottus rhotheus ) appeared in 23 of the samples 

 and sixty-seven sites sampled evidenced no sculpin. 

 Additionally, 3 of 31 re-sample sites contained sculpin while 17 

 sites within lakes revealed no sculpin. In all, 156 sites were 

 surveyed, principally in the Kootenai River, Tobacco River, and 

 Stillwater River drainages. 



Torrent sculpin had a broad distribution geographically, while 

 slimy sculpin were more longitudinally dispersed in the tributary 

 streams of the major rivers in the study area. Based on the 

 limited sampling in this survey, torrent sculpin distribution 

 generally appeared to be restricted to tributary streams of the 

 Kootenai River in close proximity to the main river. However, 

 torrent sculpin were present at distances greater than 5 km from 

 the Kootenai on Tobacco River tributaries, Libby Creek, Fisher 

 River, and Big Creek. 



Two sites exhibited potential for sympatry between torrent and 

 slimy sculpin. Hybridization potentially exists between these 

 two species but was not confirmed in this study. The extent of 

 niche partitioning by these species in areas of overlap was not 

 studied. 



Sculpin habitat was characterized as riffle or a combination of 

 run/riffle/glide habitat with some degree of cobble substrate. 

 Sculpin were generally found at sites with gradients from 3-4%. 

 Substrate composition is likely an important physical factor 

 influencing sculpin density and distribution and warrants further 

 study. 



Species-specific stream habitats were indistinguishable in this 

 study. Qualitative evaluations of stream habitat were used to 

 assess differences between sites. Individual species habitat 

 requirements were similar enough to require that quantitative 

 measures of a number of physical, chemical, and biological 

 conditions be made before distinctions could be determined for 

 individual species. 



Electroshocking in conjunction with D-netting was the best method 



