6 SALMON AND TROUT IN ALASKA. 



ling stage, is followed by a detailed record of the field observations 

 on the young, and upon these data, which are largely statistical, is 

 based the succeeding discussion of the habits of the salmon from the 

 time of the migration of the young until the return of the adults to 

 the spawning beds. Liberal use has been made in this discussion of 

 the results of previous workers on the subject, and, in addition to the 

 collections and notes made by the shore parties in Alaska in 1903, 

 1904, and 1905, all of the Albatross collections of young salmon now in 

 possession of the Bureau have been studied. The concluding chapters 

 of the report are given to the discussion of questions relating to the 

 adult salmon, and contain in tabular form the statistics of weights 

 and measurements of nearly 10,000 sockeye salmon, with anatomical 

 counts of about 4,600 of these. In the entire paper the sockeye, as 

 the most valuable commercial salmon of Alaska, has been made the 

 main feature. 



DISTINCTIVE CHARACTERS OF THE SPECIES. 



COMMON NAMES. 



The most common appellations of the various species as they are 

 known in Alaska are used in this paper. There seems to be no reason 

 why, for example, the words ''quinjiat," ''chinook," and "king," 

 which in a loose way pertain, respectively, to the Sacramento, Colum- 

 bia, and Alaskan tschawytscha, should be continued to the confusion of 

 readers. The ''blueback" of the Columbia differs in no specific 

 essential from the '^ sockeye" of Alaska. Names based on characters 

 common to several species, such as ''red," "silver," etc., are 

 especially apt to be confusing. The name "trout" as here applied 

 to small fingerlings may include steelhead, rainbow, and cutthroat. 

 Individual variations in both trout and salmon overlap the limiting 

 points in most characters, but in the salmon the sum of various char- 

 acters sets the five American species distinctly apart. Careful exami- 

 nation has so far failed to show any distinguishing character to 

 differentiate the young of these trouts. Indeed, apparently no specific 

 difference is constant in the adult. 



DIFFERENTIATING MARKS IN ADULTS. 



Fishermen and large handlers of salmon roughly but very accu- 

 rately distinguish the adults of different species by certain obvious 

 characters. The king salmon is known by the small black spots on 

 the tail. The tail of the humpback is spotted, but with larger oblong 

 spots. The backs of both king and coho are commonly spotted, the 

 spots of the coho being as a rule smaller than those of the king, but 

 these spots are not noted by fishermen. Rarely the sockeye shows a 

 few spots, particularly on the tail, but these are never distinct as in 

 the other species. (To the sea-run form only does this statement 



