NO MARKS 



FISHERY BULLETIN: VOL. 75, NO. 1 

 MARK 1 MARK 2 MARK 3 MARK 4 



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DISTANCE (MM X 42) 



FIGURE 7. — Distance from scale margin 

 to the last mark or to the focus if no 

 marks were present. 



months. Scales with three marks showed the third 

 mark being formed throughout the warm months, 

 the only period when scales with only three marks 

 were available. Scales with four marks were 

 observed only during March. The increment on 

 these scales suggests that the fourth mark was 

 formed during winter or spring. However, further 

 data are needed to establish this. 



Our findings on times of mark formation agree 

 with Haven's (1954) suggestion that croaker form 

 one fall and one winter mark each year in 

 Chesapeake Bay and with Richards' (1973) 

 computer-simulated findings that the related 

 black drum, Pogonias cromis, forms one mark a 

 year until maturity and two marks a year 

 thereafter. 



116 



