Brodeur et al.: Distribution, growth, condition, origin, and associations of juvenile salmonids 



37 



hatcheries in the Umpqua River (n=5), Rogue River (n=l), 

 and Columbia River (n=2) were in our study area. 



Genetic analysis of steelhead samples showed that a 

 large proportion were from the Rogue River and nearby 

 coastal streams (53%, SD=0.08). Steelhead from the Sacra- 

 mento and San Joaquin rivers (14%, SD=0.05) and north- 

 ern California coastal rivers (10%, SD=0.05) were also 

 present. Estimates for steelhead originating from rivers 

 north of Cape Blanco and from south of the San Francisco 

 Bay were near zero. Approximately 19% of the steelhead 

 mixture was not allocated to any source population, sug- 

 gesting that our baseline data for the species is incomplete. 

 No steelhead in our collections contained CWTs. 



Species associations of juvenile salmonids and other 

 species 



From cluster analysis of species based on station assem- 

 blages (Fig. 6), MRPP of both sample periods showed strong 

 within-group agreement (P<0.0001) at the first level (two 

 groups); all subsequent groups had sequentially higher 

 levels of within-group agreement. As a result, the cutoff 

 level was determined by balancing a lower percent infor- 

 mation remaining (<30%) in the model while retaining bio- 

 logically meaningful groups. For June this cutoff resided at 

 the second level (three groups) and for August, at the third 

 level (four groups ). For the June cruise, all salmonids includ- 



