^'♦ 



Salmonidae of Norway. 75 



The result of the marking of fish in Norway shows 

 that no hard-and-fast rule can be made as regards the 

 increase in weight of fish from one year to another ; in 

 fact, as in most points concerning the natural history of 

 the salmon, we must not pay too much attention to 

 exceptions, but rather base our calculations upon the 

 general average. 



Herr Landmark says that fish weighing from I2 to 

 3kgs. in one year increase on an average 100 per cent. ; 

 fish of from 3 to 5 kgs. increase 50 per cent. ; fish of from 

 5 to 7 kgs. increase 40 per cent. ; fish from 7 to 9 kgs. 

 increase 25 per cent. ; and, lastly, fish of from 9 to 

 12 kgs. increase 20 per cent., which means that a fish 

 of 27 lbs. would increase in weight about 5l lbs. in a 

 single year, which, more or less, agrees with the calcu- 

 lations of experts in this country as regards British 

 salmon. 



It must be remembered that a 27 lb. fish will lose from 

 4 to 5 lbs. in weight during spawning, and in the course of 

 a year he regains this loss of 4 to 5 lbs., and increases in 

 weight to another 5 lbs. or so, making a total increase of 

 about 10 lbs. between the kelt stage and the date when he 

 next ascends the river as a fresh fish. 



The last question I shall attempt to deal with in regard 

 to the salmon is, how often does he spawn ? 



I must again revert to Herr Landmark's investigations, 



