FISHERY BULLETIN: VOL. 69. NO. 4 



1958 year class had nearly passed from the 

 fishery. 



The greatest decline in abundance has been 

 in the Middle and North Atlantic areas, where 

 older fish constitute the bulk of the catches. 

 Fish pumps and airplane spotters, two of the 

 improvements having the most impact on fishing 

 effectiveness, increased sharply in both areas 

 after 1949. Yet the catch per vessel week, after 

 reaching a peak in about 1952, declined there- 

 after in both areas, despite other fishing improve- 

 ments added in the middle 1950's. In the North 

 Atlantic, the catch per vessel week, except for 



1952 and 1953, was no greater from 1950 through 

 1962 than it had been from 1941 to 1950. In the 

 Middle Atlantic, the catch per vessel week, al- 

 though being substantially greater from 1952 to 

 1962 than it had been up until 1951, began a 

 steady decline in 1957, and from 1963 to 1966 

 was much lower than in the years prior to 1950. 

 From these data one may conclude that the 

 abundance of menhaden in these two areas was 

 no greater from 1950 to 1962, and considerably 

 less after 1962, than it had been prior to 1950. 



The decline in abundance in Chesapeake Bay, 

 where 1- and 2-year-old fish compose most of 

 the catches, has not been as great as in the 

 North and Middle Atlantic. The catch per vessel 

 week was substantially greater from 1954 to 1962 

 than it was prior to 1954 or after 1962. Since 

 the major improvements in fishing methods came 

 a few years later than in the Middle and North 

 Atlantic, the higher catches per vessel week after 



1953 probably reflect an increase in fishing effi- 

 ciency, although they could reflect an increase in 

 menhaden abundance. The decrease after 1962 

 probably resulted from a true decrease in men- 

 haden abundance. 



Abundance in the South Atlantic, where age-1 

 fish compose most of the catch, appears to have 

 remained unchanged. The catches per vessel 

 week varied widely, but showed no trend. In 

 this area the fisheries at the three ports are 

 small, geographically distinct, and dependent on 

 relatively small numbers of fish, principally of 

 one age group, that are dispersed over a large 

 area. If the carrying capacity is less in the South 

 Atlantic than in other areas, the abundance of 

 fish in the area is less likely to reflect changes 



in the total Atlantic menhaden population than 

 is the abundance of fish in areas of high density 

 and high carrying capacity, such as Chesapeake 

 Bay. 



In the North Carolina fall fishery menhaden 

 nearly always will appear to be abundant, be- 

 cause they are concentrated in a small area for 

 a short period of time and are easy to catch. 

 But since weather is more variable than in other 

 areas, it influences the catch per vessel week 

 more than it does elsewhere. The wide fluctu- 

 ations in the catch per vessel week, therefore, 

 do not necessarily reflect variations in abun- 

 dance. 



The relation between the decline in abundance 

 and the high levels of fishing effort can be under- 

 stood only if the spawning age, the age and size 

 distribution, and the seasonal movements of the 

 fish are considered. Atlantic menhaden spawn 

 after they have completed three growing seasons 

 (Higham and Nicholson, 1964), and rarely sur- 

 vive past seven growing seasons. Their age and 

 size distribution and seasonal movements have 

 been described by June and Nicholson (1964) 

 and Nicholson,' and are briefly summarized here. 



During the fishing season from about May to 

 October, the population from Florida to Chesa- 

 peake Bay is composed primarily of age-1 and 

 age-2 fish. Although the proportion of each age 

 group varies with the strength of individual year 

 classes, age-1 fish are usually more abundant, 

 particularly south of Cape Hatteras. From the 

 mouth of Chesapeake Bay to Long Island, age-2 

 fish gradually replace age-1 fish as the dominant 

 age group. Age-3 fish, dominant in Long Island 

 and Nantucket Sounds, become less abundant 

 north of Cape Cod, where age-4 to age-7 fish 

 predominate. A southward movement begins 

 among fish at the northern end of the range 

 in late summer and extends to all fish north of 

 Cape Hatteras by early November. By mid-Jan- 

 uary nearly all menhaden have moved into the 

 offshore area between Cape Lookout and north- 

 ern Florida. In late winter these fish begin a 

 northward movement. 



' Nicholson, William R. Movements of Atlantic men- 

 haden as inferred from changes in age and size distri- 

 bution. (Unpublished manuscript.) 



780 



