— 122 — 



suitable places, we must conclude that a quantity of the cod grow up in the strand-region, 

 from the first bottom stages up to a length of 50—60 cm. 



The strand-region is however by no means the only place where the cod grow up; 

 the medium cod can also be taken in somewhat deeper water along the whole coast, and 

 in the northernmost part of Norway in Finmark and in the neighbouring Barentz 

 Sea there are quantities of the medium-sized, especially in spring, when the "lodde" 

 {Mallotus villosus) approach the coasts to spawn. Cod of all sizes but chiefly the 

 medium-sized pursue these small fish. See the uppermost curve in fig. 50, which shows 

 the different sizes of cod taken in a haul in spring at Finmark. 



The older cod over 60 cm. in length are only taken in any large quantities in 

 spring during the spawning time on the coastal banks. These large cod have received 

 from the fishermen a separate name "skrej" , and a special skrej fishery is carried on 

 from the Norwegian North Sea coast northwards as far as to the southern boundary of 

 the district Finmark. As can be seen from fig. 51 (see explanation), the skrej consists 

 for the most part of fish between 60 — 90 cm. in length. 



It is evident that a statistical treatment of catches of such a varied nature can 

 scarcely lead to any deeper understanding of the relation between the different groups. 

 On the other hand, the age determinations, which as already mentioned are based 

 on the investigation of the scales, have advanced our knowledge a good deal. 



As these investigations have so great an importance for the understanding of the 

 natural history of the gadoids, we may here, referring also to Damas' paper, discuss 

 somewhat more closely the structure and growth of the gadoid scales. 



When the cod is about 5 cm. long, some small comb-like elevations, which Damas 

 calls "crêtes élémentaires", form about the small scale-centre and then arrange them- 

 selves round this in a circle. The small circles formed in this way may be called 

 "elementary rings". They arise during growth and their number stands in relation to 

 the length of the fish, though not so that all scales show an equal number of such small 

 rings. If, however, we always choose scales from the same part of the body for invest- 

 igation, e. g. on the side under the dorsal fins, the variation is very small. It appears 

 that, when the different individuals of the same year-group display very different sizes, 

 the number of the elementary rings is also very different. Thus, for example, different 

 individuals of the o-group in the North Sea had from 5 to 30 elementary rings. 



Whenever the growth of the fish proceeds regularly, the elementary rings also show 

 a regular distance from one another. When, however, the growth is slower or as in 

 winter at a standstill, not only the rings decrease in number but the distance between 

 them is also smaller. The winter elementary rings on a scale form together a winter ring. 



A weak concentration of the rings may also occur in summer in the cod of some 

 regions, yet they can never be confused with the winter rings. 



It appears from these notes on the growth of the scales, that they can yield us in- 

 formation on the following points: 



