FISHERY BULLETIN: VOL. 85, NO. 3 



y 



5*'s 



4's 



3's 



02's 

 1's 

 O's 



56 58 60 62 64 66 68 70 72 74 76 78 80 82 



YEAR 



Figure 8. — Contribution in percent of total numbers of Atlantic menhaden landed by age group, from 1955 to 



1981. 



y 



s 



5+'s 



4's 



3's 



2's 



1's 



O's 



Figure 9. — Contribution in percent of total biomass of Atlantic menhaden landed by age group, 



1981. 



from 1955 to 



SPAWNER-RECRUITMENT 

 RELATIONSHIP 



Estimates of Numbers of Spawners 



Higham and Nicholson (1964) concluded that a 

 few age-1 Atlantic menhaden and most age-2 fish 

 are sexually mature by the end of the season. The 

 simplifying assumption for purposes of estimat- 

 ing spawning stock in these analyses is that no 

 age-1 fish and all age-2 fish are mature by the 



beginning of the fourth quarter. This assumption 

 was also used in other studies (Nelson et al. 1977; 

 ASMFC fn. 4; Schaaf and Huntsman 1972). 



Estimates of the number of fish age 2.75 and 

 greater alive at the beginning of the fourth quar- 

 ter of any given year n comprised the parental 

 spawning stock for year class n + 1. The esti- 

 mates of number of spawners resulting from the 

 1947-64 year classes were obtained from the 

 mixed time-interval VPA series. The number of 

 spawners from the 1965-78 year classes were ob- 



582 



