PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1923. 37 



but, as in previous seasons, large numbers of them were not sexually 

 mature. All immature fish taken were carried above the dam and 

 released. 



SALMON (IDAHO) SUHSTATION. 



With tiie recently constructed buildings near Salmon, Idaho, as 

 headquarters, temporary egg-collecting stations were established in 

 this field on the Lemhi, Pahsimeroi, and Yankee Fork Creeks, and 

 at Sunbeam Dam. The run of salmon was light at all points, but 

 especially so at Yankee Fork, and the work there was abandoned 

 early in the season, it being apparent that eggs could not be ob- 

 tained in numbers sufficient to warrant the expense of maintaining 

 racks. 



After being developed to the eyed stage, the eggs collected from 

 the various streams in this region were transferred to the hatchery 

 at Salmon for incubation. The year's distributions from this sub- 

 station included 1,124,700 chinook salmon, 236,000 rainbow trout, 

 and 99,000 brook trout, all fingerlings. The output of the two species 

 of trout was the result of transfers of eggs made from other stations. 



A further examination of the Salmon River district was made 

 during the year, and from the evidence obtained on this and previous 

 trips it appears certain that at least a majority of the sockeyes in 

 the Columbia River originates in lakes in the Sawtooth Alountains. 

 The species was first observed in the Salmon River, near Bay Horse 

 Canon, in August, and at Sunbeam Dam some 10 days later. It was 

 further noted that salmon entered most of the tributaries of the 

 three rivers inspected. It is not probable that fish enter all these 

 streams in large numbers, but at the time of the inspection each 

 stream appeared to have a run. 



BAIRD (CALIF.) STATION AND SUBSTATION. 



[\V. K. Hancock, Supeiiutendent. ] 



The results of the year's fish-cultural work at all points in the 

 California field were discouraging in the extreme, the egg collections 

 and the output of young fish being the smallest since the inception 

 of the bureau's fish-cultural operations in the State. 



While extremely low water stages prevailed everywhere in this 

 region during the spawning season, hampering the run of fish, and 

 other climatic conditions were not altogether favorable, the verji' 

 unusual scarcity of fish on their wonted spawning areas can hardly 

 be attributed to natural causes alone. The principal reasons for the 

 decline must, for the present at least, be the subject of conjecture. 

 Among the theories advanced have been (1) excessive fishing by 

 purse seines in the lower Sacramento River and (2) loss of fish 

 through their entrance into the numerous irrigating ditches recently 

 constructed. 



Pecidiarities noted in connection with the season's work at both the 

 substations in the California field were the large size of the few 

 spawning females taken and the excessive numbers of undersized 

 and immature males present. However, at the Baird station, on the 

 McCloud River, the mature females exceeded the males in number. 



