_ 37 — B. HELLAND-HANSEN 



comparatively few individuals occur belonging to the 1903 year-class. In 1905 we 

 notice the effect due to 1904 in the large number of individuals of group I 

 which now occur. The 1902 — 3 year-classes are still only slightly represented. 

 And in 1906 there is an exceedingl>' large quantity of haddocks spawned in 1904, 

 while the 1905 year-class is not nearly so much in evidence. 



So that we arrive at the same result as before: in 1902 and more noticeably 

 in 1903 the haddock-supply of the North Sea received a very small accession of 

 new young individuals, while 1904 brought an extremely large addition. 



This then is what we find in the Great Fisher Bank area, but we meet with 

 exactly the same state of affairs on the Dogger Bank (fig. 27) and off Flamborough 

 Head (fig. 26). The years 1900, 1901 and 1904 brought many new individuals to 

 these areas, while 1902 and more noticeably 1903 brought comparatively few. In 

 these two areas the average catches in 1904 were particularly small. 



The figure for the Northern area shows other conditions (fig. 25). Here during 

 the summer of 1904 there was a considerable number of individuals spawned in 

 1903. In fact the largest portion of the catches consisted of individuals from that 

 year. But in 1905 these had disappeared. 



What we have stated then fully justifies the assumption previously arrived 

 at, and makes it absolutely certain that there are very great variations from year 

 to year in the accession of new individuals within the various areas. And for the 

 years here considered one fact in particular appears to admit of no doubt, that in 

 the southern and mid portion of the North Sea extremely few individuals spawned 

 in 1903 were added to the haddock-supply. The question therefore naturally 

 arises: is this due to want of spawning, or to active or passive wanderings of the 

 youngest stages of haddock? To this question, if we rely on statistical material 

 alone, we can give no satisfactory reply. And I will confine myself to stating 

 hat the occurrence in the Northern area of haddocks spawned in 1903 may be 

 explained by assuming either migration northwards of the young fish of that 

 year or a relatively more intense spawning in 1903 in the Northern areas than in 

 the Southern ones. I would further refer the reader to the remarks of Damas 

 upon this question. 



III. Weight 



In the material which we are here considering there is a great deal of in- 

 formation as to the weights of haddocks. To a large extent however it consists 

 of reports giving only the total weights of the various catches; and insufficient 

 details are to hand concerning the weights of the different individuals. Details of 

 this nature are to be found combined with age-assessments in the large material 

 collected of haddock from the Norse coasts, which will be more fully treated 

 elsewhere (cf. Damas). The following study of the conditions of weight only 

 relates to the North Sea and is based on Fulton's earlier investigations into the 

 relation between length and weight. In this way we have included all the catches 

 that are comprised in our material, and we have thus tried to analyse the 

 distribution of weight in the average catches. The accuracy is no doubt rather 



