POPULATION AND FISHERY CHARACTERISTICS OF 

 ATLANTIC MENHADEN, BREVOORTIA TYRANNUS 



Dean W. Ahrenholz,' Walter R Nelson,^ and Sheryan P Epperly' 



ABSTRACT 



A stock assessment analysis of the Atlantic menhaden, Brevuortia tyrannus, fishery was conducted 

 with purse seine landings data from 1940 to 1981 and port sampling data from 1955 to 1981. Virtual 

 population (cohort) analysis was used to estimate historical stock sizes, rates of fishing, and numbers 

 of recruits. The population exploitation rate (age 1 and older) ranged from 0.29 to 0.51 and averaged 

 about 0.38 for the 1955-79 period. Recruitment at age 0.5 during the 1955-79 period ranged from 1.5 

 to 18.6 billion fish, with a mean of 5.1 billion. Classical spawner-recruitment relationships describe 

 the data poorly. Growth and mortality data were used to examine yield per recruit for temporal and 

 geographic fishing areas and for the entire fishery. Size at age data, while supporting an earlier 

 hypothesis of density-dependent growth, show a trend toward slower apparent growth in the 1970's 

 than is explained by this hypothesis alone. Yield per recruit of Atlantic menhaden dropped from 107 g 

 for the 1970-72 period to 57 g for the 1976-78 period. A Graham-Schaefer production model estimate 

 of maximum sustainable yield (MSY) for the 1955-79 period was 414,000 metric tons. A modified 

 Pella-Tomlinson production model provided a MSY estimate of 557,000 metric tons. The latter esti- 

 mate is probably unattainable given current temporal and geographic fishing patterns. Results of 

 these analyses indicate that the Atlantic menhaden fishery suffers from growth overfishing. 



Some fishing activity has been conducted on At- 

 lantic menhaden, Brevoortia tyrannus, since colo- 

 nial times, but the purse seine fishery and factory 

 reduction activities began in New England about 

 1850 (Reintjes 1969). The geographic range of the 

 modern reduction fishery was established by the 

 1930's (Nicholson 1971a) and the fishery under- 

 went substantial expansion following World 

 War II. Good discussions of the actual fishing op- 

 erations and types of gear involved are contained 

 in Reintjes (1969) and Nicholson (1971a). 



With the exception of the 1950 fishing season, 

 the Atlantic menhaden fishery has dominated 

 total U.S. fishery landings in volume since 1946, 

 when the Pacific sardine, Sardinops sagax, fish- 

 ery was declining. This dominance continued 

 until 1963, when, during its own decline, Atlantic 

 menhaden landings were surpassed by the gulf 

 menhaden, Brevoortia patronus, purse seine fish- 

 ery. Gulf menhaden landings have dominated 

 U.S. fishery landings since, and Atlantic men- 

 haden currently account for about one-third of the 

 total menhaden landings. 



The U.S. Fish and Wildlife Service, Bureau of 



'Southeast Fisheries Center Beaufort Laboratory, National 

 Marine Fisheries Service, NCAA, Beaufort, NC 28516. 



^Southeast Fisheries Center Beaufort Laboratory, National 

 Marine Fisheries Service, NOAA, Beaufort, NC; present ad- 

 dress: Southeast Fisheries Center Miami Laboratory, National 

 Marine Fisheries Service, NOAA, 75 Virginia Beach Drive, 

 Miami, FL 33149. 



Commercial Fisheries"^ began biological investi- 

 gations on Atlantic menhaden in 1952. Studies 

 were initiated during what were, in retrospect, 

 peak landing years with the goal to determine the 

 nature of population fluctuations and variability 

 in geographic abundance (June and Reintjes 

 1959). Following the marked reduction in stock 

 abundance that occurred in the late 1960's, stud- 

 ies were initiated to determine probable causes 

 for the decline and to develop management op- 

 tions to avert a second decline. 



The fishery for this migratory clupeid takes 

 place primarily within states' jurisdictional 

 waters (<3 miles from shore), and managerial 

 authority rests with the individual states. Coast- 

 wide management plans are cooperatively formu- 

 lated under the auspices of the Atlantic States 

 Marine Fisheries Commission (ASMFC), but the 

 implementation requires separate legislative or 

 regulatory action by each member state. Individ- 

 ual states are not obligated to act upon coopera- 

 tively derived plans or management actions from 

 the ASMFC. 



Stock assessment studies provide fundamental 

 scientific information required to formulate 

 coastwide management actions. An early evalua- 

 tion of the stock status of Atlantic menhaden, 



Manuscript accepted April 1987. 



FISHERY BULLETIN: VOL. 85, NO. 3, 1987. 



3Presently the National Marine Fisheries Service (NMFS), 

 NOAA, U.S. Department of Commerce. 



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