FISHERY BULLETIN: VOL. 70, NO. 2 



12 1. 6 



6 1.2 1.8 .6 12 18 6 12 18 



FISHING MORTALITY RATE (F) 



12 1.8 



Figure 15. — Calculated total yields (in kilograms) for 1961 and 1962 brood 

 Spring Creek hatchery fall chinook salmon for different natural mortality rates 

 and fishing on only one age group at a time. 



7,000 



5,500 



4,000 



g 2,500 



o 



111 

 a. 



o 



O 1.000 



5,500 



4,000 



2,500 



1,000 



1961 BROOD 

 M = 24 



\ \ 



1962 BROOD 



.4 5 



60 



72 



.96 



-- F^ 



1.2 18 



6 1.2 1.8 .6 1.2 1.8 6 12 18 



FISHING MORTALITY RATE (F ) 



1.2 1.8 



Figure 16. — Calculated total yields (in kilograms) for 1961 and 1962 brood 

 Kalama hatchery fall chinook salmon for different natural mortality rates and 

 fishing on only one age group at a time. 



444 



