36 



NOTE : Incerprecation of this information is complex and Che effect of 

 straying is cumulative and dependent upon fitness of strays. If 

 fitness of strays is equal to fitness of natural spawners, then the 

 proDortion of the gene pool composed of natural spawning fish in the 

 first year of the series (62V) is further decreased by each of the 

 following years by the added proportion of addixional strays into the 

 spawning population in subseqpjent years. Thus, unless fitness of 

 strays is an extremely low value (close to zero) , the composition of 

 the gene pool of the fish called "natural spawners" at the current 

 time is primarily composed of progeny of strays, not progeny of 

 "natural spawners". 



' Hatchery fish likely strayed above Lower Granite Dam prior to 1983; however, 

 no estimates of this potential straying are available because coded wire tag 

 technology used to document this phenomena was not available nor used on 

 potentially straying hatchery populations of fall chinoo)c prior to this 

 time. 



2 The 1994 estimate of strays entering the escapement past Lower Granite Dam 

 has not yet been split into the Sna)ce and Columbia River components. 



Table 5. 



EstiT.ated r.umfcer of fall chinock passing Lower Granite Dam ar.d 

 for Lyons Ferry Hatchery brood stoc)<, 1975-1994. 



