Summary 



A total of 76 sculpin (Cottus) samples were taken from the Kootenai National Forest 

 and portions of the Lolo National Forest in northwestern Montana. Slimy sculpins (Cottus 

 cognatus) were present in 46 of the collections. Torrent sculpins (Cottus rhotheus) 

 appeared in 21 of the samples. Shorthead sculpins (Cottus confusus) were present in 14 of 

 the collections. Five of the collections contained more than one sculpin species. 



Slimy sculpins had a broad distribution both geographically and longitudinally on the 

 tributary streams of the major rivers in the study area. Based on the limited sampling in 

 this study, torrent sculpin distribution appeared to be restricted to tributary streams of the 

 Kootenai River in close proximity to the main river, although torrent sculpins were present 

 at distances greater than 5 km from the Kootenai on Tobacco River tributaries. Shorthead 

 sculpin distribution was difficult to decipher. There is some speculation that shorthead 

 sculpin distribution is closely linked with Glacial Lake Missoula. It is possible that 

 shortheads were the first sculpin species to colonize drainages after the draining of Glacial 

 Lake Missoula. Shorthead sculpins appeared to be the only sculpin species inhabiting the 

 St. Regis River watershed. Four additional shorthead sites were found outside this 

 watershed in sympatry with slimy sculpins. Three sites were located in the Yaak River 

 drainage and a fourth site was found on a tributary of the lower Clark Fork River. All three 

 sculpin species occurred at sites within and downstream of lands under multiple use 

 management. 



Slimy sculpins were found in sympatry with torrent sculpins at two sites and in 

 sympatry with shorthead sculpins at four sites. Hybridization potentially exists between 



