materials had no detectable influence on population means of chinook salmon. Chinook 

 salmon were found in third, fourth, and fifth order streams, with their numbers increas- 

 ing as the stream order increased. Fifth order streams contained 76 percent of the 

 Chinook salmon collected. Chinook salmon occurrence was influenced most by the proxim- 

 ity of the stream reach to the river. 



Salmon Occurrences as Related to Geomorphic Type 



Chinook salmon were found in six landtypes within two of the four landtype associ- 

 ations (fluvial and depositional) occurring in the study area. Fluvial lands are lands 

 formed by the erosive force of running water. Depositional lands are formed by water 

 and glacial soil deposits. No chinook salmon were collected in the cryic landtype 

 association, nor in the flaciated landtype association almost barren of fish, with only 

 rainbow trout being found in the glacial trough landtype. 



Chinook salmon dominated the fish populations in the alluvial and alluvial fan 

 landtypes, and their populations occurred mainly in these low channel gradient areas in 

 close proximity to the river. Chinook salmon were also found in streams within the 

 moraine, dissected mountain slope, terrace, and valley train landtypes. 



SUMMARY 



Juvenile summer chinook salmon made unexpected use of the tributary streams; they 

 were found in 69 percent of the tributaries sampled. They were the second most 

 numerous fish species, following the resident and anadromous forms of rainbow trout, 

 which were usually found living with chinook salmon. 



Sculpin were found with chinook salmon in all but two tributary areas; and brook 

 trout, Dolly Varden, mountain whitefish, sucker, and dace were occasionally found in 

 the same stream areas. 



Chinook salmon preferred high quality pools found in the larger streams, with 

 lower channel gradients and grassy streambanks. They were most numerous in channel 

 elevations between 4,800 and 5,200 feet ( 1,460 and 1,580 m) . Chinook salmon were found 

 mostly in the alluvial and alluvial fan landtypes, with the closeness of the stream 

 reach to the river as the most important variable determining whether chinook salmon 

 occurred or not. 



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