■157- 



n 1 1 1 1 1 1 1 r 



62 

 40 

 24 

 13 



7 

 3 



\ 1.5 /-oisc; 



to 



Q 



2 



O 

 CL 



a. 





0.2 0.4 0.6 0.8 1.0 1.2 1.4 



MULTIPLIER 



1.8 2.0 



Figure 7. Yield-per-recruit isopleths for yellow- 

 fin tuna inside the CYRA; a) based on 

 the age structure of the catch during 

 the period 1968 to 1972 and natural mor- 

 tality rate M=0.8, b) based on the age 

 structure during the period 1973 to 

 1978 and M=0.8, c) based on the age 



