16 EEPORT OF THE COMMISSIONER OF FISHERIES. 



posing futile obstacles to the development of a legitimate and essen- 

 tial industry. The work of the division of scientific inquiry of the 

 bureau is directed to the acquisition of this knowledge and its adapta- 

 tion to the needs of the fisheries, its principal activities during the 

 fiscal year being epitomized in the following pages. 



STUDIES OF FISHES. 



The salmon fisheries of Alaska present the most critical problem 

 of fishery conservation confronting the bureau at the present time, 

 the intensity of the fishery developed during recent years having 

 very seriously depleted the runs in some streams, while almost every- 

 where the diminution has made itself manifest to a degree threaten- 

 ing eventual disaster. As is explained in more detail elsewhere 

 in this report, the laws under which the bureau has been endeavoring 

 to conserve this fishery are inadequate, and it has been necessary to 

 invoke the powers of the President to create fishery reservations to 

 give the immediate control of the situation necessary to save the fish. 



Wliile studies made during the past decade have added much to 

 knowledge of the habits and life histories of the Pacific coast sal- 

 mons, their wide distribution from California to the Arctic, the dif- 

 ferences in environment through their range, and the fact that 

 practically each stream has its own exclusive school of fish, makes 

 their study laborious, time-consuming, and difficult. With the 

 purpose of preparing a sound basis for regulatory measures that will 

 conserve the fish while permitting the maximum safe exploitation 

 of the fisheries, the bureau for a number of years past has engaged 

 specialists to conduct the necessary investigations. 



The enumeration of the salmon passing into Karlak River, on 

 Kodiak Island, which has been referred to in previous reports, was 

 continued during the year and a similar work was undertaken at 

 Chignik. These studies are intended to furnish data of the ratio 

 of fish on the spawning grounds to the total run necessary to main- 

 tain an unimpaired supply. 



In an effort to determine the composition of sea schools of salmon 

 in respect to the location of their spawning streams, about 4,000 

 adult fish were marked with aluminum tags at various places on or 

 near the Alaska Peninsula. A considerable percentage of these was 

 retaken, and valuable data were obtained regarding the oceanic 

 migrations of the fish. This work will be supplemented and ex- 

 tended by tagging about 10,000 fish during the fiscal year 1924. A 

 report on the progress of these studies was published during the 

 year. Since 1916 nearly 750,000 young salmon have been marked 

 by cutting off various of the fins and liberating them in the Co- 

 lumbia, Sacramento, and Quinault Rivers. On their return to 

 the streams after several years spent in the sea these fish are easily 

 recognized. During the" spring of 1920, 100,000 young sockeye 

 salmon, reared from eggs brought from Alaska in 1918, were so 

 marked and liberated in the Columbia River with the invaluable 

 cooperation of the Oregon Fish Commission. In 1922 large numbers 

 of these, grown to maturity, returned to the river, and scales and 

 data from approximately 1,200 were obtained. This, of course, 

 does not represent the number entering the river. The fish, both 

 in external appearance and qualities of flesh, retained the char- 



