REPORT OF THE COMMISSIONER OF FISHERIES. 17 



acters of their Alaskan ancestry, being distinctly different from 

 native Columbia River fish of the same species. 



Many of the important former spawning grounds of the blueback 

 salmon of the Columbia River have been made inaccessible by the 

 construction of power and irrigation works, and in 1922 an investi- 

 gation was made to locate the spawning places now resorted to. It 

 was found that a spawning run progresses at least to Sunbeam Dam 

 on Salmon River, Idaho, and that the improvement of the fishway 

 at that place to make it more readily passable to fish bound for 

 Redfish Lakes should be undertaken. 



The investigations on the Coregoninse, or whitefishes, which are 

 among the most important commercially of the Great Lakes, have 

 been continued ; the field work was completed early in the fiscal year, 

 iind the attention of the investigators has been directed for some 

 months to the examination and comparison of collections and the 

 compilation of data to be included in the final report on the system- 

 atic relations and natural history of the various species. Many data 

 bearing on the differences between various races of whitefish and 

 other coregonine fishes are now available, and especial attention is 

 being given to the life history of the whitefish. The University of 

 Michigan and the State Biological Survey are evincing a fine spirit 

 of cooperation, which will materially aid and advance the work. 



For a number of years the bureau made investigations, as oppor- 

 tunity occurred, of the salmons, trouts, and smelts of the Atlantic 

 coast, but the work was suspended in 1921 on the resignation of the 

 assistant who had been conducting it. It was resumed during 1923 

 on the return of the investigator to the service, and considerable prog- 

 ress has been made in assembling the accumulated data for publica- 

 tion. Some light has been thrown on the complicated relationships 

 of the trouts, and material is on hand for clearing up certain puzzling 

 matters of particular interest to fish culturists and anglers, but dur- 

 ing the year attention has been devoted chiefly to smelts, which are 

 important economically both as local food supplies, as entering into 

 commerce, and as food for other fishes. As a consequence of the 

 assiduity with which the smelt fisheries have been prosecuted, the 

 supply of fish is being depleted gradually, and the report in prepara- 

 tion w411 be comprehensive of all facts relating to them that may be 

 significant in efforts toward their conservation where still abundant 

 and their increase in waters that have been depleted. 



In cooperation with members of the faculty of the University of 

 Wisconsin, studies of the natural foods of fresh-water fishes, par- 

 ticularly the basses, sunfishes, and perch, in wild waters, have been 

 conducted with very small assistance from the bureau. 



The available fisheries of interior waters and of the streams falling 

 directly into the sea, as a whole, are now exploited to their permissible 

 limits, and in some cases already mentioned are showing more or less 

 marked indications of exhaustion. For increased production of 

 fish food to meet the demands of growing population recourse must 

 be had to that great reservoir of food, the sea. Of the strictly 

 marine fishes none of the more important species, with the exception 

 of the halibut, are exhibiting the criteria of depletion excepting, per- 

 haps, locally ; but with a conceivably possible but by no means immi- 

 nent large increase in consumption, such symptoms may manifest 



