A study on trout and young salmon. 



(Report on researches concerning the migrations of young salmon 

 1898-1902) 



by 

 Knut Dahl 



director of the biological station, Trondhjem. 

 (With 3 plates and 7 tables.) 



Introduction. 



Ever since Linné in the year 1766 published his Systema 

 Naturae, the treatment of the genus, to which trout and salmon 

 belong, has thrown considerable difficulties in the way of syste- 

 matical investigation, because these species or forms are very 

 closely related as well in external and internal caracters as in 

 their habits of hfe. 



Linné distinguished the following species: 

 Salmo salar = salmon. 

 „ eriox = sea trout. 

 „ trutta = river trout. 

 „ fario = brook trout. 

 „ lacustris = lake trout. 

 These Linnés 5 species have in the course of time encoun- 

 tered quite a remarkable fate. 



During the past century a series of naturalists have occu- 

 pied themselves in investigating their right as distinct species. 

 Swedish scientists principally have closely studied these species, 

 although other european savants f. ex. Guvier, Pallas' 

 Agassiz sen., Kröyer, Siebold, Günther, Day and Yarrel 



