no 



. , Weight in kg. 



Average number „", . , ° 



^ pr. nshmg hour 



1.8 



"Unmarketable" . . . i.e | 



"Codling" 2.4 f 



Cod 0.8 ' 4.3 



Total ... 4.8 6.1 



It we consider now the numbers, it is apparent that Vs^''^ o^ *^he total catch 

 of cod with the trawl consists of the "unmarketable" specimens. In the case 

 of the haddock only '/yth was on an average "unmarketable". The steam trawlers thus 

 catch a considerable proportion of the stock of cod in the unsaleable condition. In 

 relation to the weight these small cod constitute only an inappreciable part of the catch. 

 Three times as many "codling" occur as "cod", but by weight the entire class of "codling" 

 constitutes barely the half of the class "cod". 



The average size for the inception of maturity in the cod of the North Sea is 

 placed by the different authors at somewhat different sizes , from 60 to 65 cm. If we 

 place it at 60 cm. it agrees with the limit between the small and large cod. We may 

 conclude from the figures given above that only '/eth of the catch is composed of mature 

 specimens. In the North Sea region investigated, consequently, a much smaller number 

 of mature cod was found in proportion to the total than mature haddock 

 in comparison with the total quantity of haddock in the hauls with 

 the trawl. 



With regard to the variations in the numbers from year to year, these were very 

 considerable in the case of the smaller sizes. The percentage of the "unmarketable" 

 amounted to only 14 in 1903 and to 62 in 1906, of the "codling" only 23 in 1906 and 

 65 in 1903. 



The large cod on the other hand showed almost the' same proportion to the total 

 catch in all the years. It seems, therefore, that similar fluctuations also occur in the yearly 

 natural increase of the cod, as have been already described in the case of the haddock, 

 and that there may be good and bad year-groups among the younger fish. Owing to 

 the essentially too small material we cannot discuss these important conditions here in 

 detail, but may refer to Helland-Hansen's paper. 



We come now to the grouping of the cod according to the age. In contrast to 

 the more abundant haddock material, which enabled more definite determinations to be 

 made, the available cod material is not sufficient to enable us to determine the growth of 

 the cod even in the younger year-groups. This is shown by Helland-Hansen in detail 

 in his discussion of the large number of curves which have been drawn on the basis 

 of the separate hauls. We are obliged to restrict ourselves here to the age deter- 

 minations. 



In the section on the cod in the Norwegian Sea a more general account of the results 

 of these age determinations will also be given for the North Sea. We may just mention 

 here that Damas has investigated cod from the region north of the Dogger Bank taken 

 in September. It proved that 



