86 THE AGE AND GROWTH OF SALMON AND TEOUT. 



Maiden fish which have not spawned are shown in ordinary figures ; 

 those with a spawning mark are placed in brackets. 



These tables tell us several things of great importance. 



Firstly we notice that the salmon does not live many years after 

 migration. Most of the fish have spent from one to three winters in the sea. 

 A salmon, whose scales show more than four winters after migration, is an 

 extraordinary exception. 



In the same way the tables show us that the large majority of the fish, 

 on which our fisheries depend, consists of fish which have not spawned 

 before and which are entering the river for the first time to spawn. It will 

 also be noticed that these maiden fish are not all of one age, but may 

 have spent from one to four winters in the sea before they attained sexual 

 maturity. 



This clearly shows that the salmon, which in each year are the material 

 for our fisheries, and which are making their way up to the rivers, are not 

 the whole of the fish in existence. They form only a portion of the various 

 year-classes to which they belong, a portion which is on the point of becom- 

 ing sexually mature, and which, as it were, has broken away from the rest 

 for the purpose of spawning. This is made even clearer by an investigation 

 of the eex of the fish. It was impossible for me to include such investiga- 

 tions with my analysis of age on a large scale, for it would have necessitated 

 cutting each fish open, the expense of which would have been prohibitive. 

 I have, therefore, been compelled to restrict myself as far as this point is 

 concerned to investigations on a small scale. 



In Table XIV., I have given the results of such investigations. I cut 

 open and examined the sexual organs of forty -eight small salmon caught in 

 the district between Trondhjem and Finmarken in the beginning of July. 

 All the fish which had completed only one winter in the sea, as will be seen 

 from the table, were males. The hen fish were only to be found when I 

 came to examine fish which had spent two winters in the sea. 



As will be seen from all the tables the fish which have spent one winter 

 in the sea vary in length between something over 40 centimetres and about 

 67 centimetres, and by measurement alone we were therefore able to dis- 

 tinguish a good many of the one winter old fish (see for example Table VIII.). 



Now we have a number of measurements taken from a good many 

 rivers of the size of parent fish, which had been obtained for hatching pur- 

 poses, and which after spawning had been used for marking experiments. 

 In these measurements the sexes have been carefully distinguished. Herr 

 Landmark, the Government Fishery Inspector, has kindly lent me his list 

 of these measurements. 



With the help of these I have compiled all the available measurements 

 relating to the size of each sex from the Aaensire, Laerdal and Drammen 



