PEOGRESS IN BIOLOGICAL INQUIRIES 17 



ALASKA SALMON 



The investigations of the Alaska salmon conducted by Dr. C. H. 

 Gilbert and Dr. W. H. Rich have yielded important information dur- 

 ing the past year. The study of migrations by means of tagging; 

 experiments was continued, nearly 16,000 tags having been attached. 

 Two thousand of these were put on in the Port Moller region of the 

 Bering Sea, the remainder being used in southeastern Alaska. The 

 results of the experiments conducted at Port Moller corroborated the 

 findings of 1922 to the effect that the majority of the fish taken at 

 that place are of local origin, spawning mainly in the Bear and Sandy 

 Rivers. The experiments in southeastern Alaska "furnished much 

 information regarding the migrations of the various species of salmon 

 among the complicated channels of this region, but the situation here 

 is so complex that it is not possible to summarize the results briefly. 

 During the year a report was published covering the results of tag- 

 ging experiments in 1923, and a report on the tagging experiments of 

 1924 and 1925 is in course of preparation. 



The intensive study of the important salmon runs at Karluk, 

 Chignik, and the red-salmon streams of Bristol Bay has been continued 

 by Doctor Gilbert. Weirs have been operated continuously since 1921 

 at Karluk and since 1922 at Chignik, and during each of these years 

 the escapement of salmon to these streams has been determined by 

 actual count of the fish passing through the openings in the weirs. 

 Weirs have been maintained at Alitak and in Anan Creek also. The 

 first returns from escapements of known size will occur on the Karluk 

 River in 1926 and at Chignik in 1927. The results are awaited with 

 much interest, and we can look forward to a series of determinations in 

 successive years that should present evidence of the highest value. 

 Through these investigations an attempt is being made to determine 

 such correlations as exist between the number of spawning fish and 

 the number of their progeny that return at maturity. This will 

 give a measure of the total losses that occur from the egg to the 

 adult from all causes combined, and will answer the all-important 

 question as to the size of the spawning reserve needed to produce a 

 run of the desired size. 



Rapid pi ogress has been made by Doctor Gilbert in the survey of 

 the cycles and the annual composition of the red-salmon runs to the 

 various streams of Bristol Bay. Extensive collections of scales from 

 this region have accumulated and represent the runs of several years. 

 The scales of some 15,000 red salmon included in these collections 

 were read during the past year and the results tabulated. 



SALMON OF THE PACIFIC COAST STATES 



A series of salmon-marking experiments, which have been con- 

 ducted for a number of years on the Columbia River by the bureau 

 in cooperation with the Oregon Fish Commission, yielded valuable 

 information during the 1925 season. Approximately 100 adult chi- 

 nook and 50 sockeye salmon, which had been marked by remov- 

 ing certain of their fins when they were liberated from the hatcheries, 

 were recovered as they returned to the Columbia River to spawn. 

 The sockeyes represent the first returns from 100,000 yearlings that 

 were marked and liberated during February, 1924. The recovery 



