18 REPORT OF THE COMMISSIONER OF FISHERIES. 



cause for action, a decline in production of shad remains a topic for 

 conversation. 



This is not to say that the exhaustion of fishery resources is in- 

 evitable or that the decline of fisheries has not in some instances been 

 arrested or retarded. In many cases, though not in all, effective 

 results have been gained by the application of measures of production 

 and propagation as far as has been permitted by the knowledge avail- 

 able and by the public will. Investigations pursued in the past have 

 yielded a certain fund of knowledge regarding propagation, habits, 

 and conditions of life of fishes, and upon such knowledge is based 

 both the fish-culture work that is so extensively pursued in the United 

 States and the great body of sound protective measures whenever in 

 effect. Were the fund of knowledge greater, artificial propagation 

 would be more successful and economical and would no doubt be 

 effectively extended to other species, while protective legislation would 

 be more wisely framed and more successful in the accomplishment of 

 its purpose. 



Never, perhaps, has there been greater demand for the applica- 

 tion of knowledge regarding fishes to practical ends for 'the public 

 good, while yet there is no proportionate demand for the discovery 

 of the knowledge that can be given application. 



During the past year the bureau has endeavored to apply its lim- 

 ited resources to the problems of the fishes in the most effective man- 

 ner, having regard, inevitably, to the qualifications and experience 

 of its available personnel and to the limited funds and equipment. 

 The story of the progress and accomplishments in biological investi- 

 gations is told in the following pages. 



STUDIES OF FISHES. 



Extensive studies were conducted of the runs of salmon in Alaska 

 to determine the facts necessary for effective regulation of the fish- 

 eries, to the end that they may be maintained and improved. An 

 important feature of this work is the determination of the proportion 

 of the runs that must be permitted to escape to the spawning grounds 

 in order that the natural increase may compensate for the fish cap- 

 tured before spawning. The bureau has accumulated some informa- 

 tion on this subject in connection with its fish-cultural operations at 

 Baker Lake and Quinault Lake, Wash., but conditions vary with 

 the locality, and before the results can be generally applicable in 

 a practical Avay it will be necessary to make careful studies in a num- 

 ber of streams presenting diverse physical conditions. During the 

 jear a rack was established in Karluk River, on Kodiak Island, and 

 careful check was kept of the number of salmon passing to the 

 spawning grounds after escaping the fishery conducted entirely below 

 the point of observation. Studies of the life history and migrations 

 of the salmon of the Pacific Coast States have been continued as in 

 previous years. 



Investigations of the fishes of the whitefish family have been 

 continued and during the fiscal year were extended to Lake Superior. 

 Some of these fishes are of great present commercial importance 

 and others have potential value but are not now exploited because 

 of tlieir place of occurrence, the ignorance of the fishermen concern- 

 in <»• their habits and habitats, or the inhibitions imposed by laws and 

 ico-ulations made for the protection of some other species. 



