- 400 



-300 



200 



UJ 

 O 

 < 



\- 

 Z 

 LU 

 O 



ct 



UJ 

 CL 



100 



Figure 10. --Production (solid line), abundance index (long 



dashes), and fishing-intensity index (short dashes) 

 for chubs in the combined districts of the State of 

 Michigan, 1929-1953. Scale at left applies only to 

 production; scale at right is in terms of 1929-1913 

 mean. 



21 



