36 



Several explanations for the affinity of sculpins to rubble substrates exist. The 

 interstitial spaces common in rubble substrates offer refuge from predatory fish and birds. 

 Sculpins typically attempted to escape the electroshocker by burrowing into the substrate. 

 In addition, rubble substrates typically support higher concentrations of aquatic insects 

 which is thought to be the primary sculpin food source. 



Torrent sculpins appeared more capable of tolerating habitat with some degree of finer 

 substrate material than the other two sculpin species. This may, in fact, be an indirect 

 measure of some other habitat parameter influencing torrent distribution (i.e. torrents might 

 prefer warmer stream temperatures which is a characteristic of slower moving bodies of 

 water in Montana). 



