I I r^] I II I — I I I I "' I 



80 100 I 20 I 40 160 1 60 2 00 220 240 2 60 260 300 3?0 340 360 

 FORK LENGTH (MM.) 



Figure 7.--Length frequencies of males and females in 

 samples from purse seine catches of Atlantic men- 

 haden. 1958. 



TABLE 7. — Sex ratios in samples from purse seine 

 catches of Atlantic menhaden, hy area, 1958 



by weight), with a peak at 65 g., and of age-2 

 fish, with a less distinct peak at 105 g. 



In Chesapeake Bay, the weight frequencies of 

 age-1 fish (39 percent of the catch by weight) 

 and age-2 fish (60 percent of the catch by 

 weight) were indistinguishable and represented 

 by a dominant mode at 135 g. 



In the Middle Atlantic Area, where age-2 

 fish constituted 97 percent of the catch by 

 weight, a dominant mode appeared at 225 g. 

 The positive skewness of the curve resulted 

 primarily from the presence in the catch of 

 fish older than age 2. 



In the North Atlantic Area, the weight of age- 

 2 fish (approximately 40 percent of the catch 

 by weight) were distinguishable up to about 

 400 g., and an ill-defined peak may be seen at 

 305 g. in figure 8. Over the remainder of the 

 range, there was no concentration offish in any 

 one weight class. 



In the North Carolina fall fishery, four 

 distinct size groups were evident. The first 

 group, ranging up to 80 g. in weight, with a 

 mode at 15 g., consisted entirely of age-0 fish 

 which appeared for the first time in numbers 

 in the 1958 catch. The second weight group, 

 from 80 to approximately 210 g., was com- 

 prised primarily of age-1 fish. Except for the 

 shift to the right (as a result of the summer's 

 growth), the remaining portion of the curve 

 resembled that for the North Atlantic summer 

 catch, with age-2 fish (over 50 percent of the 

 fall catch by weight) accounting for the major 

 portion of the size group from approximately 

 210 to 500 g. 



Average Length and Weight 



Mean lengths and weights offish, by age, sex, 

 and area, in 1958, are listed in appendix 

 tables 11-15 and by age, area, and season, 

 1955-58, in tables 8 and 9. With the exception 

 of fish caught in the Chesapeake Bay Area, 

 the mean lengths and weights in 1958 were 

 less than those in 1957 (last column in tables 

 8 and 9). The greatest decreases occurred in 

 the North Atlantic Area and the North Carolina 



15 



