CONTENTS. 



INTRODUCTION v 



CHAP. 



I. METHODS OF INVESTIGATION 1 



1. Salmon Scales 1 



(a) The Scales of Parr and Smolts before Migration . . ~ . 2 



(&) The Scales after Migration 6 



(c) The Scales after Salmon have returned to the Eiver. 



Formation of Spawning Mark . . . . . . 14 



2. Trout Scales 16 



The Spawning Mark 19 



3. General Observations on the Use of Scales as a means towards the 



Determination of Growth . . 19 



II. ON SALMON 30 



1. The Age and Characteristics of Parr and Smolts before Migration . 30 



2. The Salmon after Migration 33 



(a) The Age of Smolts at the Period of Migration ... 34 



(i) The Age of Salmon after Migration 35 



(c) The Growth of Salmon after Migration ..... 40 



(d) The Relative Occurrence of the Different Year- Classes in 



Different Localities 43 



(e) The Distribution of the Year-Classes 51 



III. ON TROUT 53 



A. Instances of Sea-Trout and of the Eivers to which they have Access . 54 



B. Instances of Trout from Waters to which Sea-Trout have no 



Access 62 



1. Lake Mj0sen Trout - .. . . 62 



2. Trout from other Lakes 67 



IV. GENERAL CONCLUSIONS AS TO THE PROBLEMS CONNECTED WITH THE 



GROWTH or SALMON AND TROUT 72 



a 2 



