88 REPORT OF THE COMMISSIONER OF FISHERIES. 
the salmon industry, to the end that a clearer understanding of the 
problems involved might be obtained. 
Incidental to the salmon investigations numerous dredgings were 
made by the steamer Albatross at various depths in the straits and 
fiords of southeast Alaska and about Kadiak Island, Afognak Island, 
and Yakutat. These investigations had in view the development of 
the aquatic fauna of Alaska, and resulted in large and interesting col- 
lections, not only of fishes, but of mollusks, crustaceans, and other 
invertebrates. These collections have been assigned to specialists for 
study and report. 
The salmons of the Pacific.—The salmons of the Pacific differ nota- 
bly, as a whole, from the single species called salmon (Sadmo salar) on 
the coasts of the North Atlantic. Anatomically they differ in several 
details of structure; in habits the distinctions are still more marked. 
Normally, the Atlantic salmon survives the reproductive act and 
returns to the rivers at the spawning time for several years. The 
Pacific salmons, on the other hand, have more definite runs. The 
greater part of their lives is spent in the sea, and they run into fresh 
water only at spawning time. During this period they take no food 
of any kind, the oil of the body is consumed, the flesh becomes dry 
and pale, the jaws of the males hecome much elongated and distorted, 
the front teeth are enlarged, the color is changed, and the whole body 
becomes greatly distorted. Death follows within a few days after 
spawning. There is no evidence that any individual of any species of 
Pacific salmon ever survives the reproductive act. 
All the Pacific salmons spawn on a falling temperature, when the 
water is already cool and becoming colder. Freezing kills the eggs, 
but any temperature between 54° F. and freezing is favorable to their 
development; above the former point the eggs develop precociously 
and the young fish are apt to die. In the more northern rivers a 
temperature of 54° is reached earlier, and for this reason the run 
of salmon occurs earlier in those regions than in the southern waters 
of Alaska. All the species spawn by preference in running water, 
though occasionally some individuals spawn in lakes. The spawning 
beds are usually on gravel bars, and in the spawning act the gravel is 
pushed about, not for the purpose of covering the eggs, but rather as 
a part of the spawning act itself; pressure against the gravel aids in 
the extrusion of the eggs. The male covers the eggs with milt, and 
in so doing also moves the gravel about to some extent. This fact is 
a matter of importance where different species, or different schools of 
the same species, spawn upon the same beds, the later comers disturb- 
ing more or less seriously the eggs of those which have preceded them. 
There are five species of salmon in Alaska and neighboring waters, 
and they are identical with the species found on the coasts of British 
Columbia, Washington, Oregon, and California. These five species 
