- 25 



B. HELLAND-HANSEN 



.■■■■■■■■■•jy..-. 



/ ffl '■■■ 



The catch consisted of 126 individuals, of which 123 were measured. None 

 of them were less than 20 centimeters, so that the average for the I group 

 (I'/a years) is uncertain; since there were doubtless many smaller fish belonging 

 to the same group which have not been caught. 



Fig. 9 is a graphic represen- yi 



tation of these measurements. .■••\.---.y 



The unbroken curve gives the 

 composition of the total catch. 

 The first two length-groups are 

 very prominent. The dotted 

 curves show the sittiation and 

 size of the different year-groups, 

 and it will be seen that the 

 two first length-groups exactly 

 correspond with age-groups I 

 and II. The succeeding groups 

 overlap, so that it would not 

 have been possible to define 

 them properly by length-measure- 

 ments alone. Similar relations LtnerH ,m cEn-nm^xERs 

 are to be seen in by far the Fig. 9. Age-distribution as per scale-investigations in a catch 

 «■reat majority of the curves of haddock from the Great Fisher Bank area (August 1906). 

 which denote the catches: the smallest groups of haddock are often 

 sharply defined and characteristic, whereas the larger groups 

 overlap. As a rule it is only groups I and II that can be ascertained. 

 The o-group may be here entirely disregarded. 



Fig. ro — 14 are instances of curves showing the catches of haddock at different 

 seasons. They all have reference to the same area D. These curves reseinble 

 many of the others and are quite ordinary in appearance. Thus one will at once be 

 struck by the sharply defined grouping of the smaller sizes and the overlapping 

 of the later groups. The average sizes on ist August 1906, which we have 

 previously given, are shown by the broken vertical lines. Here we can easily 

 remark the year-classes, which the clearly-defined length-groups represent. It will 

 be noticed that these groups lie halfway between the vertical lines noted in March 

 and that, to take an instance, the first of them (I group) approaches more and 

 more towards the first vertical line as the summer advances. We can accordingly 



