ON TROUT. 



55 



Here we meet once more with an age distribution similar to what we 

 found to be the case with salmon smolts from the same district, that is to 

 say, the majority are three to four years old when they repair to the sea. 



The tables in my previous publication " 0rret og Unglaks " gave some 

 interesting information as to the size of these sea trout smolts, as I measured 

 a number of them when they were actually migrating from the rivers of 

 the Trondhjem district in May and June. Their length varied between 

 10 cm. and 20 cm. 



For purposes of comparison I have also made out the following 

 calculation of the sizes of the young fish at the time of migration from 

 measurements of the scales of the sea trout referred to in Table XVII. 

 I selected in this connection the 118 fish which had lived one winter 

 subsequent to migration. 



From the above we see that the calculated lengths of the sea trout 

 smolts range from 10 cm. to a little over 20 cm., being about the same extent 

 of variation which I previously found in the actual measurements of smolts 

 caught at the mouths of the rivers of the Trondhjem district, but we 



