Table 4. --Number of areas in which each fish species was found in combination with other fish species in the 

 tributaries of the SFSR 



Species : 



Alone : 



Rainbow : 



Chinook : 

 salmon • 



Sculpin 



: Dolly : 

 I Varden ; 



Eastern 

 brook 



• 



Cutthroat i 



Mountain : 

 whitefish : 



Dace 



: Sucker 



Rainbow 



12 





12 



10 



5 



5 



4 



3 



1 



2 



Chinook 























salmon 







1 2 





11 



2 



3 







2 



1 



1 



Sculpin 



1 



10 



11 





2 



3 







2 



1 



1 



Dolly 























Varden 



13 



5 



2 



2 





3 



2 















Eastern 























brook 



3 



5 



3 



3 



3 









1 



1 







Cutthroat 



4 



4 











2 





















Mountain 























whitef ish 







3 



2 



2 







1 









1 







Dace 







1 



1 



1 







1 







1 









Sucker 







2 



1 



1 

























found with chinook salmon. Chinook salmon were found with Dolly Varden, mountain white- 

 fish, and mountain suckers in only two streams, and with dace in Cabin Creek, the only 

 Stream containing dace. Finding chinook salmon in Cabin Creek was unexpected because 

 it was believed that the Cabin Creek culverts were impassable to migrating adult salmon 

 and steelhead trout. 



The standing crop information demonstrates the controlling effect that anadromous 

 fish can have on resident fish. If chinook salmon and steelhead trout populations 

 disappeared from the SFSR, the lower reaches of the tributaries would undoubtedly be 

 used more by resident trout species. 



Salmon Densities Related to Aquatic Habitat Conditions 



Juvenile chinook salmon preferred stream areas containing high quality pools, with 

 55 percent occurring in pools with excellent ratings (Platts 1974) . Pool condition 

 accounted for 8 percent of the chinook salmon's observed variation in population numbers. 

 However, even though chinook salmon preferred high quality pools, 59 percent were found 

 in stream areas where the percent of channel in pool was less than 20 percent. This 

 can be explained by chinook salmon preferring lower tributary reaches that naturally had 

 a low pool/riffle ratio. Seventy-one percent of the chinook salmon collected were in 

 stream reaches with widths more than 30 feet (9.1 m) . 



As average channel gradients increased from 2 to 4 percent, mean chinook salmon 

 numbers per stream length increased. As channel gradients increased above 4 percent, 

 chinook salmon numbers declined and were not found in channels exceeding 10 percent 

 gradient . 



Chinook salmon in the study area reared in channels with elevations between 3,600 

 and 5,600 feet (1,100 and 1,710 m) , with 52 percent occurring between 4,800 and 5,200 

 feet (1,460 and 1.580 m). These channel elevations corresponded to most of the tribu- 

 tary confluences with the SFSR. 



Sixty-one percent of the chinook salmon collected were in channels dominated by 

 grassy streambanks. The lowest densities found were in channels dominated by forested 

 streambanks because chinook salmon reared mainly in the lower elevations where grassy 

 streambanks dominate. The stability of the streambank and the composition of channel 



9 



