shows several prominant size groups. The 

 smallest fish ranged from about 70 to 125 

 ram. , with a mode at 87 mm. A second peak 

 occurs 157 mm. , followed by prominent peaks 

 at 247 and 302 mm. As in the previous year, 

 several of the major size groups which 

 contributed to the summer catches north of 

 Cape Hatter as were well represented in the 

 North Carolina fall fishery. It appears 

 that the variation in the relative contri- 

 bution of the various size (and age) groups 

 to the North Carolina fall catch is due 

 partly to the availability of the fish and 

 partly to size selectivity on the part of 

 the fishermen. Adverse weather often inter- 

 rupts fishing during the period when certain 

 size groups are passing through the area, 

 hence these may not be represented in the 

 catch in proportion to their actual abun- 

 dance. Furthermore, as bodies of larger, 

 heavier fish appear on the grounds, groups 

 of smaller fish already present in the area 

 often are ignored, even though they still 

 may be abundant and within range of the 

 fishing fleet. 



Conparison of the average lengths and 

 weights of fish at each age by area in 1955 

 and 1956 is made in table 6 (See Appendix 

 tables 15-21), The dominant year class in 

 each area is underscored. The data show 

 that fish of the dominant year class which 

 contributed to the catch in each area, with- 

 out exception, were shorter and lighter in 

 1956 than in the previous year. Slight 

 irregularities in the average length and 

 weight pattern result, in part, from the 

 comparatively small numbers of fish repre- 

 sented in the several age groups. Also, 

 certain age groups appeared in the samples 

 at varying times during the season in both 

 years and hence are not strictly comparable. 

 Whether the decrease in size of the dominant 

 age groups in 1956 was the result of envi- 

 ronmental conditions, including food pro- 

 duction, is unknown. It is possible that 

 the greater abundance of fish on the summer 

 grounds in 1956 may have limited the amount 

 of food available to individual fish, thus 

 resulting in an apparent decrease growth 

 rate. 



Data for both years show that fish of 

 the same age were largest and heaviest at 

 the northern end of the range and smallest 

 and lightest at the southern end. Also, 

 females were larger and heavier at older 



ages than the males, and these differences 

 were greatest in northern waters. Varying 

 sex ratios between years among the older 

 age groups (age 4 and older) also affect 

 the average lengths and weights given in 

 table 6; however, this is of no significance 

 among the younger age groups. 



SUMM\RY 



1. The 1956 catch of Atlantic menhaden 

 ( Brevoortia tyr annus ) was 766,000 tons, 

 of which 740,000 tons were caught by 

 purse seines. Record catches occurred 

 in the Middle Atlantic and North Atlan- 

 tic Areas. 



2. Apparent abundance, as measured by the 

 catch per purse-seine set, was lowest 

 in Chesapeake Bay (13.9 tons) and high- 

 est in the North Atlantic Area (35.2 

 tons) . 



3. The most productive fishing grounds 

 (200 sets and over) were located (1) 

 off Fernandina Beach, Fla.; (2) off 

 Capes Fear and Lookout, N. C. ; (3) in 

 lower Chesapeake Bay; (4) along the 

 coasts of Virginia, Maryland, Delaware, 

 New Jersey, and the western end of Long 

 Island; and (5) Massachusetts Bay. 



4. Age composition of sanples from the 

 catches indicated that the 1955 year 

 class (age-1 fish) dominated the fish- 

 ery in 1956, contributing an estimated 

 2.07 billion fish. Following in order 

 of importance, the 19^4 (age 2), 1953 

 (age 3), and 1951 (age 5) year classes 

 also made substantial contributions 



to the catches. The 1955 year class 

 dominated in the South Atlantic and 

 Chesapeake summer catches and the North 

 Carolina fall catch; the 1954 year 

 class (age-2 fish) dominated in the 

 Middle Atlantic Area; and the 1951 year 

 class (age-5 fish) dominated in the 

 North Atlantic Area. 



5. Length composition of the catches showed 

 that smaller length groups were encoun- 

 tered in most areas in 1956 as compared 

 with the previous year. Also, average 

 weights and lengths of fish in the domi- 

 nant year class in the individual areas 

 were smaller in 1956. 



11 



