- 54 - 



The two catches which followed one another so closely that the trawl for the 

 second drag was shot almost as soon as the first was hauled, show clearly the 

 haphazard way in which cod occur in these regions of the North Sea. 



There are many curves showing the same even distribution of all the sizes 

 which we find on the lowermost curve in fig. 34. If we put together the results 

 from stations quite near each other at the same season there do not appear to be 

 any particularly distinct groupings in the curve showing the sum. The only 

 group in fact about which anything could be said is the I-group. 



n 



\ 

 \ 

 \ 

 \ 



50 55 60 65 70 75 80 85 90 95 100 105 110 115 "izo 



Fig- 35- Length-measurements of several catches of cod, made by Scotch trawlers. I. From the 



Northern part of the North Sea, between 6o° and 6i° N. Lat , March— April 1905. II. From the 



North Sea off the East Coast of Scotland (56-58° N. Lat, 0—2° W. Longi, April 1904 



I have attempted several similar combinations of the different catches. For 

 instance by combining all the catches from the same area and month and again 

 by amalgamating all the catches in the North Sea for a given month. Not even 

 thus however have I succeeded in obtaining from our material distinct groups 

 which might serve to show the size of the different year-groups or the rate of 

 growth of the cod, as we were able to do in the case of haddock (compare fig. 15) 



There are several reasons to account for this. As is well known the spawning 

 of the cod in the North Sea lasts for a considerable space of time, since the fish 

 spawn along the coasts during the first months of the year and farther out to sea 

 as the season advances. Indeed in some places, as for instance the Lingbank, it is 

 well on in the summer before spawning takes place. This alone causes considerable 

 variations in the sizes of cod, even although spawned in the selfsame year. 



Further the rate of growth of different individuals varies greatly in different 

 parts of the North Sea. These differences in size have especially been noticed in the 



