FISHERY BULLETIN: VOL. 85. NO. 3 



for the subsequent years when population size 

 was decreasing. The rates reached their lowest 

 points for ages 1-3 during 1960, when the 1958 

 year class was fully recruited. A low point fol- 

 lowed for ages 4 and 5 during 1961. All exploita- 

 tion rates generally increased during the low re- 

 cruitment years of the 1960's, and began 

 decreasing during the 1970's as the population 

 size began to increase due to higher recruitment. 

 The rate of reduction noted for nominal effort 

 (Fig. 1) lagged behind that of the stock and was 

 apparently too slow to prevent the observed rise 

 in exploitation rates during the 1960's. 



The exploitation rates of age-2 fish appear to 

 have progressively declined during the later 

 1970's, following a disproportionately large in- 

 crease after 1971. This increase apparently was a 

 product of a shift in the pattern of fishing that 

 occurred during the regrowth of the fishery and 

 that pattern still exists. Although slightly lag- 

 ging behind that of the age-2 fish, exploitation 

 rates on age-0 fish began increasing by 1974, and 

 reached an alarming rate of about 15% in 1979 

 (preliminary estimate). This rate of exploitation 

 occurred in virtually one quarter of fishing and 

 slightly exceeded the rate of exploitation for age-1 

 fish for the entire season. The disproportionately 

 low exploitation rate on age I's is probably due to 

 their increasingly smaller size, a consequence of 

 which would be a more southerly distribution. 

 Additionally, many would remain in or near estu- 

 arine nursery areas and surrounding smaller 

 bays and sounds, and thus be less available to the 

 fishery. 



ACKNOWLEDGMENTS 



We are grateful to the many individuals who 

 contributed to the countless tasks involved in the 

 development and maintenance of the complex 29- 

 yr Atlantic menhaden data set. Donnie L. Dudley, 

 Joseph E. Hightower, John E. Hollingsworth, 

 David E. Hopkins, Charles W. Krouse, and Larry 

 L. Massey made significant contributions to vari- 

 ous aspects of data collection and processing and 

 analytical computer model development and im- 

 plementation. Gary T. Sakagawa provided help- 

 ful suggestions for analytical approaches. Alex- 

 ander J. Chester, Charles S. Manooch III, John V. 

 Merriner, William R. Nicholson, William E. 

 Schaaf, and Douglas S. Vaughan provided excel- 

 lent reviews and helpful comments during vari- 

 ous stages of report preparation. We thank Her- 

 bert R. Gordy (figure preparation) and Beverly W. 



Harvey (word processing) for their patience dur- 

 ing the course of the many changes we made. A 

 special thanks is due to Robert B. Chapoton (de- 

 ceased) for ideas, review, and the needed encour- 

 agement during most of the development of this 

 report. 



LITERATURE CITED 



Abramson, N. J. 



1971. Computer programs for fish stock assessment. 

 FAO Fish. Tech. Pap. 101:1-154. 

 ATLANTIC States Marine Fisheries Commission 



1981. Fishery management plan for Atlantic menhaden. 

 Atl. States Mar. Fish. Comm., Fish. Manage. Rep. 2, 

 134 p. 

 Chester. A J 



1984. Sampling statistics in the Atlantic menhaden fish- 

 ery. U.S. Dep. Commer., NOAA Tech. Rep. NMFS 9, 

 16 p. 



Clark. C W , and M Mangel 



1979. Aggregation and fishery dynamics: a theoretical 

 study of schooling and the purse seine tuna fisheries. 

 Fish. Bull., U.S. 77:317-337. 



DERISO, R. B . T J. QUINN II, AND P R NEAL 



1985. Catch-age analysis with auxiliary information. 

 Can. J. Fish. Aquat. Sci. 42:815-824. 



Dryfoos, R L . R P Cheek, and R L Kroger 



1973. Preliminary analyses of Atlantic menhaden, Bre- 

 voortia tyrannus, migrations, population structure, sur- 

 vival and exploitation rates, and availability as indicated 

 from tag returns. Fish. Bull., U.S. 71:719-734. 



Epperly, S P 



1981. A population investigation of Atlantic menhaden: a 

 meristic, morphometric and biochemical approach. MS 

 Thesis, Univ. South Florida, Tampa, 107 p. 



Epperly, S. P.. W H Lenarz, L L Massey, and W R Nelson. 



1986. A generalized computer program for yield per re- 

 cruit analysis of a migrating population with area 

 specific growth and mortality rates. U.S. Dep. Com- 

 mer., NOAA Tech. Memo. NMFS-SEFC-180, 26 p. 



Epperly, S. P., and W R Nelson 



1984. Arithmetic versus exponential calculations of mean 

 biomass. Fish. Bull., U.S. 82:446-448. 

 Ferraro, S. p. 



1980. Daily time of spawning of 12 fishes in the Peconic 

 Bays, New York. Fish. Bull., U.S. 78:455-464. 



Fox. W W , Jr 



1975. Fitting the generalized stock production model by 

 least squares and equilibrium approximation. Fish. 

 Bull., U.S. 73:23-37. 

 Henry. K A 



1971. Atlantic menhaden (Brevoortia tyrannus) resource 

 and fishery - analysis of decline. U.S. Dep. Commer., 

 NOAA Tech. Rep. NMFS SSRF 642, 32 p. 

 Higham, J R , AND W R Nicholson 



1964. Sexual maturation and spawning of Atlantic men- 

 haden. Fish. Bull., U.S. 63:255-271. 

 Judy. M. H , and R M Lewis 



1983. Distribution of eggs and larvae of Atlantic men- 

 haden, Brevoortia tyrannus. along the Atlantic coast of 

 the United States. U.S. Dep. Commer., NOAA Tech. 

 Rep. NMFS SSRF 774, 23 p. 



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