2 100 



o 80 



E 60 

 o 



o 



40 



"5 20 



Only 



54 



Escapement Past Lower Granite Dam 

 Colur ribia River Strays are Assumed to be "True" Strays 



1980 



1982 



1984 



1986 1988 

 Yea/' of Spawning 



1990 



1992 



1994 



Stray Fitness = 0.0 Q St/ay Fitnass = 0.5 D Stray Fitness = 1.0 



■a 



2 100 



80 



o 



a. 

 E 60 



40 



20 



Lyons Ferry Hatchery Brood Stock 



1980 



1982 



1984 



1986 1988 

 Year of Spawning 



1990 



1992 



1994 



■ Stray Fitness - 0.0 Q Stray Fitness -= 1.0 



Figure 15. Composition of the gene pool of the fall Chinook escapement past 



Lower Granite Dam and the Lyons Ferry Hatchery based on a simple 

 dilution model with various assumptions concerning fitness of strays. 



