500 



M-6 



-400 



1930 



1940 



1945 



1950 



Figure 7. —Production (solid line), abundance index (long dashes), 

 and fishing-intensity index (short dashes) for chubs 

 in district M-6, 1929-1953. Scale at left applies 

 only to production; scale at right is in terms of 

 1929-19U3 mean. 



18 



