TABLE 6. 



-Calculated number of Atlantic menhaden (millions) by age groups in purse seine catches, 

 by area and season, 1955-58 



[Most numerous age group underscored] 



All of the main features of the length-fre- 

 quency curves noted by June and Reintjes (1959 

 and 1960) for previous years and stated by 

 June (1961) were evident in the 1958 data; 

 however, there was a noticeable decline in the 

 proportion of large fish. The size difference 

 between sexes also persisted in 1958 (fig. 7), 

 and a distinct shift in the sex ratios had 

 some bearing on length composition in several 

 areas (table 7). For example, in the South 

 Atlantic Area, the ratio of females to males 

 changed from 0.98 in 1957 to 0.89 in 1958; in 

 Chesapeake Bay, the ratio decreased from 

 1.38* to 0.94; in the Middle Atlantic Area, 

 the sex ratio remained essentially unchanged 

 (1.03 in 1957 and 1.02 in 1958); in the North 

 Atlantic Area, it decreased from 1.12 in 1957 



*June (1961) remarked that the sex-ratio data for 

 Chesapeake Bay in 1957 may have been biased in favor 

 of females because of the difficulty of recognizing 

 testes of immature males which were partially de- 

 composed. 



to 0,99 in 1958 and in the North Carolina fall 

 fishery, from 1.18 to 0.95. The increase in the 

 number of males thus resulted in a slight 

 reduction in the size of fish contributing to the 

 catches in all but the Middle Atlantic Area 

 in 1958. No further explanation for the unequal 

 representation of sexes in the catch can be 

 added to that offered by June (1961). 



Weight Composition 



The weight- frequency distributions of fish in 

 samples from the purse seine catches are 

 listed in appendix tables 6-10. The weight- 

 frequency curves, in general, reflected the 

 dominant age group(s) which corr^ _ised the 

 bulk of the catch in the different areas, but 

 notable discrepancies are evident (fig. 8). 



In the South Atlantic Area, the asymmetric 

 curve reflected the overlapping weight distri- 

 butions of age-1 fish (58 percent of the catch 



13 



