of the regression line. From these data it 

 appears that a reasonable first approximation 

 for the total mortality coefficient of Atlantic 

 menhaden during this period would be about Z 

 = 1.20. The mortality estimates for Chesapeake 

 Bay and South Atlantic are higher than for the 



other areas. This is due, in part at least, to the 

 extensive migrations from these areas as the 

 fish approach maturity. It should be noted that 

 fishing through only the early 1960's is 

 included in these estimates— about up to the 

 time the landings began to decline drastically. 



2 3 4 



AGE (YEARS) 



Figure 35.— Natural logarithm (\n) of the catch per 

 standard vessel day in the Chesapeake Bay Area, by 

 age and year-class, 1950-65. 



Figure 36.— Natural logarithm (In) of the catch per 

 standard vessel day for the total Atlantic coast men- 

 haden fishery, by age and year-class, 1947-63. 



20 



