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B. HEU^AND-HANSEN 



Average number per trawl-hour 



1903 1904 1905 1906 



Extra Large . . . . i — — — 



Large 4 4 4 i 



Medium 11 9 5 3 



Small 30 8 5 12 



Extra Small .... 11 4 12 51 



Unmarketable . . 2 2 22 4 



Total ... 59 27 48 71 



Thus in the three smallest groups there were exceedingly large variations. 

 They were — if we exclude unmarketable — most pronounced in the case of the 

 Extra Small group; for in 1904 only four answering to this size were caught 

 per trawl-hour as against fifty-one per trawl-hour in 1906. For the higher groups 

 the variations were more restricted. Thus Large were represented by an average 

 of four individuals per trawl-hour in each of the years 1903 — 1905; in 1906 there 

 were fewer of them. Extra Large (haddock over 50 cm.) were always extremely 

 scarce, viz: 



in 1903 1904 1905 1906 



108 28 21 22 per 100 trawl-hours 



The proportion in which the various groups occur in the average-catch for 

 each of these years can be seen from the following table, in which Extra Large 

 have been disregarded: 



Percentage per trawl-hour 



1903 1904 1905 1906 



Large 6 16 8 2 



Medium 19 33 10 4 



Small 54 31 10 17 



Extra Small .... 18 13 26 71 



Unmarketable . . 3 7 46 6 



100 100 100 100 



These figures express with the greatest clearness what we have previously 

 mentioned. About half the total number consisted of Smalls in 1903, of Smalls 

 and Medium combined in 1904, of Unmarketable in 1905, and in 1906 of Extra 

 Smalls. And it is worth noting that the number of Unmarketable fluctuated 

 between such extremes, that they constituted only about a thirtieth 

 of the total trawled in 1903, and all but half the whole number of 

 individuals in 1905. 



These conditions do not entirely correspond with the real general conditions 

 in the areas investigated. As far as percentages are concerned this arises to a 

 great extent from the investigations chiefly taking place during some particular 

 season. Hence it may be that in our tables the values accorded to this smallest 



