8 XJ. S. BURKAU OF FISHERIES. 



BIOLOGY OF THE PACIFIC SALMONS. 



The salmon fisheries, very valuable in themselves, support a pack- 

 ing industry, the product of which is of still greater value. Speak- 

 ing in terms of appropriate correctness, we may say that the salmon 

 taken from the rivers and lakes of Pacific Coast States and Alaska 

 now yield each year 6 pounds of highly nutritious meat food for each 

 man, woman, and child in the United States and its possessions. 

 We enjoy and esteem these valuable economic resources now, but it 

 is a serious question if the generations to follow will derive like 

 benefits from the same waters. 



It is true that the salmon are not necessarily exhaustible like a 

 mineral resource, but that they are by nature self-perpetuative, pro- 

 vided only that present and future utilization is rightly regulated 

 and that artificial propagation is intelligently directed. The de- 

 cline of the fishery in most of the waters of the Pacific coast is clear 

 evidence that we are not yet properly meeting the requirements in 

 l)ropagation and regulation. The situation in Alaska waters, a rela- 

 tively new field of exploitation, has already reached a stage which 

 investigators assure us is critical and which may be but the begin- 

 ning of an era of decline. 



It becomes a high responsibility, then, that we find out what must 

 be done, that we study the salmons until we know fully their life 

 histories and habits and the conditions of the maintenance of the 

 runs. 



The investigations conducted by Prof. C. H. Gilbert and Mr. 

 Henry O'Malley in Bristol Bay and other Alaska waters, through 

 cooperation of the Divisions of Scientific Inquiry, Fish Culture, and 

 Alaska Fisheries, are reported fully in "Alaska Fisheries and Fur 

 Industries in 1919," « and need not, therefore, be described in this 

 connection. 



In Pacific Coast States studies of salmon have been conducted pri- 

 marily by Willis H. Rich, with particular attention to the life his- 

 tory of the chinook salmon of the Columbia Eiver. 



Considerable progress has been made in the study of the life history 

 as based on scale analysis. The necessary foundation for this work 

 was laid by studies conducted during previous years and published 

 recently under the title, " The Early History and Seaward Migration 

 of the Chinook Salmon in the Columbia and Sacramento Rivers." ^ 

 Even with the data at hand, the accurate interpretation of the adult 

 scales has proven an extremely difficult task, owing to the great di- 

 versity in the types of nuclear growth. As a result of the study of 

 large series of scale photographs and the calculations of sizes at vari- 

 ous ages of several hundred individuals, it has now become possible to 

 interpret fairly accurately the age and early history from examina- 

 tion of the scales of adult fish. From investigations ]')ursued in the 

 various tributaries of the Columbia River, it is found that many con- 

 tain distinguishable races, just as had previously been shown in the 

 case of the sockeye. The study of the chinook sahnon taken in the 



« Bower, Ward T. : Alaska Fisheries and Pur Industries in 1019. Appendix IX, Report. 

 U. S. Commissioner of Fisheries, 1019. Wasliington, 1920. 



''Rich, Willis II.: Early History and Soaward Mieration of Chinook Salmon in the 

 Columbia and Sacramento Ravers. Bulletin, U. S. Bureau of Fisheries, Vol. XXXVII, 

 1919-20, pp. 1-73. Washington, 1920. 



