removals. Detailed discussions of age 

 reading techniques for haddock and 

 problems of reliability are given by- 

 Arnold (1951), Clark (1958), Jensen 

 and Clark (1958), and Kohler and Clark 

 (1958). 



Sample lots consist of the scales 

 from 20 large or 1 5 scrod taken using 

 a stratified random sample design. 



The general method for determining 

 age composition of the various units 

 of removals is as follows: 



(1) The readings from scrod and 

 large haddock, for each statistical 

 area are summarized separately 

 by length and age, and the percent- 

 age age distribution of each length 

 is calculated. 



(2) The number of fish of each length 

 for the statistical area is broken 

 down into numbers of each age 

 for that length on the basis of the 

 percentage representation of ages 

 at each length in the sample. 



(3) Haddock and scrod compositions 

 are then added directly together 

 to obtain the total age-length 

 composition for the landings from 

 each statistical area. 



This procedure is nnodified for 5Z 

 where we have determined a combined 

 age proportion for each season and 

 used it to break down the length fre- 

 quency for each month of that season. 



Discarded Portion 



Age compositions of discarded had- 

 dock have been estimated fronn scales 

 obtained during the l6 sampling trips 

 aboard commercial trawlers. Scales 

 from 255 discard haddock v/ere col- 

 lected in 1956. Age compositions of 

 the discard for 5Z East and West are 

 given in table 23. The figures repre- 

 sent total reported discard of haddock 

 from Subarea 5, since none were re- 

 ported from 5Y. 



Landed Portion 



Age compositions for Subdivision 5Z 

 for each month of the 1 956 haddock year 

 are given in tables 24 to 62, separately 



for East and West sections andinsunn- 

 mary for both sections. 



Age compositions for 5Y for each 

 season of the 1956 haddock year are 

 given in tables 63 to 77, separately for 

 North and South sections and in sum- 

 mary for both sections. The data are 

 presented by 3-cnn. groups for economy 

 of space since, as previously nnentioned, 

 the 5Y material does not require such 

 detailed presentation as that for 5Z. 



The estimates given represent the 

 total removals landed by the fishery 

 for human consumption. 



ABUNDANCE AND EFFORT 



We have since 1931 routinely pre- 

 pared estimates of haddock abundance 

 and fishing effort for Subdivision 5Z. 

 The methods for deriving these es- 

 timates are set forth in detail by 

 Rounsefell (1957). Briefly, the proce- 

 dure consists of deriving the catch per 

 day's fishing for a standardized group 

 of large otter trawlers. Total landings 

 are then divided by the standard catch 

 per day to estinnate total effort in ternns 

 of standard trawler days fished. This 

 procedure is not applicable to the 5Y 

 fishery since the haddock fishery there 

 is of an entirely different nature being 

 largely secondary to fisheries for other 

 species and conducted by smaller and 

 medium trawlers. 



The estimates for 5Z are given in 

 table 78 by month for East and West 

 sections and in summary for the whole 

 subdivision. It will be noticed that the 

 sums of the individual "days fished" 

 entries for months do not agree with 

 seasonal totals. This is because these 

 are calculated effort figures and have 

 been done separately for each month 

 and season. 



LITERATURE CITED 



ARNOLD, EDGAR L., JR. 



1951. An impression method for 

 preparing fish scales for age 

 and growth analysis. U. S. Fish 

 and Wildlife Service, Progres- 

 sive Fish-Culturist, vol. 13, 

 no. 1 , p. 11-16. 



