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Eecent Investigations Concekning the Eedfish, Oncorhykchus nerka, 

 AT ITS Spaavning GROUNDS IN Idaho. By Barton W. Evermann and 



J. T. SCOVELL. 



. Of the 130 or more families of fishes now recognized as constituting the fish- 

 failna of North America, the one of greatest and most general interest is the Sal- 

 monidae, the family to which belong the whitetish, the salmon, and the trout. 



Whether we consider beauty of form and color, activity, gaminess, quality as 

 food, or abundance and size of individuals, the different members of this family 

 stand easily with the first among fishes. 



Confined to the north temperate and arctic regions, they abound wherever 

 suitable waters are found. In North America alone no fewer than sixty-two 

 species are found. Some of these species are confined to the smaller rivers and 

 running brooks, entering lakes or the sea as occasion serves, but not habitually 

 doing so. Such are some of the species of trout of the genera Salielinua and 

 Sabno. Others again are lake fishes, approaching the shores or entering the trib- 

 utary streams only at spawning time and then retiring again to deeper waters. 

 These are the whitefishes and lake herrings. 



Then there is another group made up of species that are marine and anadro- 

 mous, living and growing in the sea, but entering fresh waters at spawning time. 

 Such are the five species of salmon of our west coast. 



From California to northern Alaska and across to Kamchatka are found 

 five species of true salmon of the genus Oncorhynchtis. viz.: 



1. The Hump-back salmon, 0. gorbuscbu, 



2. The Dog salmon, 0. keta, 



3. The silver salmon, 0. kisutch, 



4. The Blue-back salmon, 0. nerku, and 



5. The Chinook salmon, 0. tschaioi/tscha. 



The most interesting and by far the most important of the five are the Chinook 

 and the Blue-back; and it is to the last of those two species that this paper is 

 devoted. 



In Kamchatka and Alaska this species is known as the Red salmon and is 

 commercially worth more than all the other salmon of Alaska combined. It here 

 ranges in weight from five to eight pounds, and in late summer and early f.all 

 they enter the rivers and lakes of Alaska in myriads at spawning time. In the 

 Columbia Eiver it is called the Blue-back salmon and, next to the Chinook, is the 

 most valuable fish of that river. 



