16 



the samples. As a result, the ratio of respective species' abundances at the sites as well as 

 placement within the site were not available. 



Physical. Biological and Human Influences on Sculpin Distribution 



Stream Character 



Stream character was separated into three categories; pools, runs, and riffles. 

 Distinguishing the point at which a run becomes a riffle was somewhat subjective (see 

 methods) but there appeared to be a preferred location within these three categories by all 

 three sculpin species. 



Sculpins, in general, were predominantly found in runs, and to a lesser degree, in the 

 area of overlap between runs and riffles (Figure 5). Slimy sculpins were found in runs 

 87.2% of the time compared to 12.8% in run/riffles. Torrent sculpins were located 66.7% 

 of the time in run habitat compared to 33.3% in run/riffle habitat. Shorthead sculpins were 

 located in runs 77.8% of the time compared to 22.2 % in faster moving run/riffles. None 

 of die sculpin species were found in pool habitat although sampling intensity was more 

 extensive in run/riffle habitat since this was where sculpins were most likely to occur. 



Substrate 



Rubble appeared to be the preferred substrate for all three sculpin species although there 

 were variations in the percentage of rubble verses other substrate sizes (Figure 6). Sites 

 with abundant sculpin populadons typically were dominated by rubble substrate. There 

 was a corresponding decline in sculpin abundance at sites where substrate particle size 

 decreased shifting to habitat dominated by gravels and sand. It appeared that torrent 

 sculpins were more tolerant of mixed substrate containing some degree of gravel and sand. 

 Sculpins were not present on streams which did not contain at least some degree of rubble 

 substrate. 



