126 American Fisheries Society 



during the first year or two of its life, in river water, finds it too 

 fresh for its comfort and welfare, then the only alternative is to 

 descend to the sea and seek a more favorable saline environment. 

 The effect of fresh-water surroundings on salmon migrating from 

 the sea is undeniable. From the moment that it leaves salt-water 

 the adult salmon loses condition and deteriorates. Fresh water 

 seems to be most unfavorable, it loses its appetite, it becomes 

 emaciated, weak and diseased, and its only hope of recovery is to 

 return, it may be after many weeks or many months, to the sea. 

 If the sea salmon remains too long in fresh-water it dies miserably, 

 and that indeed is the fate of whole schools of Pacific salmon, all 

 perishing, and none, it is claimed, ever again reaching the sea. 

 Whether there are exceptions is a moot question, and I have dealt 

 with it in a special report on the Life History of Canadian Salmon. 

 (Marine and Fisheries Report, Ottawa, 1908, pages 38-40). 



A fresh-run salmon is the prize most eagerly sought by the 

 sportsman. Its vigor and muscular strength, its keen alertness 

 and activity, its fighting and swimming powers, even its firmness 

 and flavor on the table, are all at their best. The commercial 

 firms who handle salmon, fresh, cured, or preserved, in cans, 

 recognize the superiority of salmon fresh from salt-water. A few 

 months in fresh water suffice to transform it, and it loses its 

 brightness, its alertness and vivacity, even its perfect shape, and 

 it becomes a thin, lank, unclean fish; a "slink salmon;" a "kelt;" 

 a black salmon, often covered with woolly fungus and disfigured 

 by wounds and deformities. Salt water is evidently normal for 

 the adult salmon; but it cannot be the stimulating cause for 

 forsaking the sea and ascending into abnormal and unfavorable 

 fresh- water conditions. 



Importance of Temperature. 



That temperature is a potent factor in encouraging or deterring 

 the ascent of salmon has been always admitted. If the fresh 

 water pouring into an estuary be too cold or too warm, if owing 

 to a dry season or light snowfall there is a paucity of water, the 

 schools of waiting salmon lingering near a river mouth, will 

 remain for a few days, or it may be several weeks before ascending. 

 They are said to be acclimatizing themselves to the new fresh-water 

 conditions facing them. With an abundant down-rush of cool 



