364 U. S. BUEEAU OF FISHERIES 



brood years remain in the ocean before returning to spawn. Obvi- 

 ously, salmon staying an extra year in the ocean before returning 

 to spawn are subject to a greater mortality since they are exposed 

 to the factors which affect their mortality for an additional year's 

 time. Hence the wide fluctuations in the rate of reproduction of the 

 spawning populations may be due in part to fluctuations in their 

 ocean mortality. 



Evidence was secured during the past season which indicates that 

 changes in the natural conditions in the streams and lakes during 

 the spawning period and early development of the salmon can bring 

 about wide fluctuations in their mortality. In fact, the relatively 

 poor leturns from the escapements of 1924 to 1928, inclusive, are 

 probably due to the abnormal conditions which were observed on 

 the spawning grounds in 1924 and 1926. Hence it is believed that 

 the varying rate of reproduction of the spawning populations may 

 be traced largely to the success or failure of the spawning salmon 

 and the death rate of the ensuing young during their existence in 

 fresh water. Therefore, the program for this investigation in the 

 future will include an intensive study and evaluation of the factors 

 which influence the success of each year's spawning population and 

 the mortality of the brood from the egg stage to the time it migrates 

 to the sea. 



CHIGNIK EIVER RED SALMON INVESTIGATION 



The activities of this investigation during the past year were 

 greatly reduced owing to the transfer of its personnel, Messrs. H. B. 

 Holmes and G. B. Kelez, to other Bureau investigations. 



A temporary assistant was stationed at Chignik from May until 

 October for the purpose of collecting fish-scale samples and the obser- 

 vation of the commercial catches for marked fish. The data collected 

 have been filed for future use. 



BRISTOL BAT RED SALMON INVESTIGATION 



Although funds were not available for a biologist to carry on field 

 work in Bristol Bay during the past year, scales of the 1934 red 

 salmon populations in this area were collected through the coopera- 

 tion of the Alaska Division of the Bureau. Scale samples and body 

 measurements of the red salmon which spawn in the Bristol Bay 

 region have been accumulating for a number of years. Funds have 

 been requested for the development of this important field of work, 

 and it is hoped that they will become available in the near future. 



PINK SALMON INVESTIGATION 



The pink salmon are found in practically all the waters of Alaska 

 but are most abundant in the southeastern section. INIillions of pink 

 salmon spawn in this section each season in its hundreds of streams 

 which vary greatly both in size and character of habitat. The Bu- 

 reau of Fisheries through its conservation policy, which was made 

 possible by the White law, has been able to build up the pink-salmon 

 populations of southeastern Alaska to a state where they are fluctu- 

 ating near their maximum level of abundance. In fact, the commer- 



