ABSTRACT 



This part of the study of the Georges Bank census data treats of the total 

 age, and the age distribution of haddock over the Bank, by statistical subarea, by 

 depth, and by bottom type in the years 1948, 1949, and 1950. 



The total abundance and the age composition varied markedly from year to 

 year and emphasized the effect of certain year classes on the catch . 



TTie distribution by subarea demonstrated that the fish were concentrated in 

 certain subareas and tJiat the age composition of the catch varied with location. This 

 distribution shifted slightly from summer to spring with the total abundance being 

 greatest in subareas J and M in summer and greatest in subarea N m spring. The 

 abundance -of older haddock was consistently greater in subareas G and H than over 

 the rest of the bank. 



The depth distribution of mature fish varied with the season and appeared 

 to be linked with the spawning and feeding migrations , In summer, greater numbers 

 and heavier 5 -year -old and older haddock were caught in water deeper than 90 fathoms, 

 but in spring these older haddock were found in shoaler water . Few haddock of any 

 age were found in dep'iis between 60 ar;d 90 fathoms during the summer months . 



Haddock occurred in greater numbers over sand than over mud bottoms, but 

 this distribution was incidental to the depth distribution. 



Mortalities, although based on 2 years' data, were consistent and decreased 

 with the increasing age of the fish and their decreasing availability to commercial 

 capture . 



Age -composition data of the commercial catch and of the census data, when 

 weighted in terms of effort of the commercial fleet, were similar, a fact which 

 attests to the reliability of the sampling methods . 



Estimates of year-class strenglJi based on the relative numbers of zero -ring 

 haddock determined from census tows were substantiated by the catch of these year 

 classes in subsequent years during census cruises and by the commercial fleet. 



