AGE OF YOUNG HADDOCK 



449 



tlierefore, that haddock, at least, do not fonn a 

 ta^fjing check. Despite the lack of volume of 

 recapture information, the available data are fa- 

 vorable to the use of scales from tagged fish as a 

 test of aire validation since the scales at recapture 

 had fjrowii (either in number of edge circuli or 

 in the total number of annuli) while the tagged 

 fisji was at liberty. 



CONCLUSIONS 



1. Haddock ages determined by scale readings 

 were compared with ages judged from length- 

 frequency curves (Petersen method). The two 

 sets of age determinations were in very close 

 agreement for the first 3 years (100 percent for the 

 fii-st year, 61 percent for the second year, and 71 

 percent for the third year). Beyond the third 

 year the length-frequency modes are obscured by 

 overlapping of the lengths for each age. 



2. The zone of closely spaced ("winter" type) 

 circuli considered to be the amiulus is formed 

 during the period August through April. Only 

 one annulus is formed during the year. 



3. Age determinations from haddock scales read 

 by different readers agreed in about 90 percent of 

 the readings. The scale annuli are usually clear 

 and easy to read. 



■i. Ages read from scales and from otoliths for 

 the same fish agreed in 62 percent of the cases for a 

 sample of Te^ fish, 1 to 3 years old. Closer agi'ee- 

 ment ( 73 percent ) resulted from the readings for 

 fish 2 to 5 years old. 



5. AVhen catch-per-day data by age class for 

 commercial haddock landings were plotted each 

 year for 10 yeare, peaks representing outstanding 

 year classes stood out from the adjacent poorer 

 year classes. These peaks could be followed from 

 year to year. 



6. From a total of 32 tagged fisli. an increase 

 in tlie number of annuli equal to the number of 

 years at liberty was noted in 29 fish. Scales from 

 2 fisli had fewer annuli than yeare at liberty : 

 one fish was in the ocean 2 years, but grew only 

 one annulus; the other fish was in the ocean 3 years 

 and grew 2 annuli. 



7. Georges Hank haddock-scale annuli are 

 formed one each year; they are true year zones 

 and age determinations from these scales are valid 

 in most of the haddock. 



LITERATURE CITED 



.VRNoi.n, Edgar L., .Ir. 



19.")1. An iinpres.sioii niethotl for preparing flsh scales 

 for age and growth analysis. Progressive Fish- 

 Culturist, vol. 13, Xo. 1, p. 11-16. 

 BiGELOw. Henry B., and William C. Schboeder. 



1953. I<"i.shes of the Gulf of Maine. U.S. Fish and 

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 p. 1-577. 

 Clark, John R. 



1958. Consistency of scale readinj:. International 

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1959. Sexual maturity of haddock. Transactions 

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Cutler, D. Ward. 



1918. A preliminary account of the production of 



annual rings in the scales of plaice and flounders. 



Journal of the Marine Biological A.ssociation of 



the United Kingdom. N.S.. vol. 11, No. 4, p. 470-^96. 



Duff, Dorothy. 



1916. Investigation of the haddock fishery, with 

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 Food and Agricultural Organization of the United Na- 

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1959. Yearbook of Fishery Statistics, vol. 9, sec- 

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 United Nations, New York.] 

 Graham, Herbert W. 



1952. Mesh regiUation to increase the yield of the 

 Georges Bank haddock fishery. International 

 Commission for the Northwest Atlantic Fisheries, 

 Second Annual Report, Part 3. p. 23-33. 

 Graham, Michael. 



1929. Studies of age-determination in flsh. Part II. 

 A survey of literature. Ministry of Agriculture 

 and Fisheries. London, Fisheries Investigations, 

 series II, vol. 11, No. 3, p. 1-50. 

 Homans, R. B. S., and V. D. Vladykov. 



1954. Relation between feeding and the sexual cycle 

 of the haddiK'k. Journal of the Fisheries Research 

 Board of Canada, vol. 11, No. 5, p. 535-542. 

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1927. Fluctuations in the hadd<K'k fishery of the 

 Bay of Fiuuly. Contributions to I'anadian Biology 

 and Fisheries, N.S., vol. 3, No. 18, p. 425-436. 

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19.58. Time of fornuition of scale annuli. Interna- 

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 KoHLER, A. C, and J. R. Clark. 



19.58. Haddock scale-otolith comparisons. Journal 

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 Uee. Rosa M. 



1920. A review of the methods of age and growth 

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