46 THE AGE AND GROWTH OF SALMON AND TROUT. 



statistics previously given to be taken as representing anything more than 

 the localities to which they refer. It is well known that the catches in 

 certain places for example, in Jaederen sometimes consist almost entirely 

 of grilse. 



The tables given above must therefore only be regarded as typical 

 examples of the fact, which long experience has shown to be correct, that 

 salmon in the north are larger than those in the south, 



What, therefore, is the reason of this difference ? 



If one fish is larger than another we are naturally inclined to think 

 that it is because it is older. 



Let us therefore again examine the statistics which have been compiled 

 from the material which we have examined from Christiansand, Trondhjem, 

 and East Finmarken. 



For the purpose of comparison let us arrange the various age-groups 

 according to their percentage. (See the accompanying table.) 



An inspection of these tables clearly shows that the salmon in the 

 Trondhjem district are distinctly older than in Christiansand, and that a 

 similar difference is noticeable between Trondhjem and East Finmarken. 



It must, however, be noted that the material from East Finmarken is, 

 unfortunately, not large, and there is also the disadvantage that it does not 

 represent the whole season. The examples of 1908 were caught in the 

 middle of July, and therefore at a time when the actual season for large 

 salmon is over, and which is generally characterised by the predominance 

 of small salmon and grilse. This table, therefore, probably gives too high 

 a relative value to the younger fish. In 1909 the buying of fish at the 

 Buganes Ice-house in Sydvaranger was discontinued at the beginning of 

 July, and consequently put an end to my collection. For the same reason 

 as before, the material collected in this season overrates to some extent the 

 larger and older fish. 



Neither of these two examples above' can therefore be regarded as 



