654 U. S. BUEEAU OF FISHERIES 



in all parts of the country became so greatly reduced by the prevailing 

 drought as to materially curtail the water supply to the hatcheries. 

 The result was a partial suspension of operations in many fields, 

 while at other points auxiliary water supply lines had to be installed 

 to prevent the loss of fish and eggs on hand. These conditions affected 

 the size of the output and necessitated the planting of thousands of 

 fish at an earlier stage than was desirable, in order to prevent over- 

 crowding of the station ponds. The drought brought about suitable 

 conditions for the capture of fish in the rescue work in the Mississippi 

 River region, but the continued low water levels at the close of the 

 fiscal year offered little prospect for a successful season during the 

 summer of 1931. 



COMMERCIAL SPECIES 



Commercial species are propagated in an effort to counterbalance 

 the drain that commercial fishing places on the fishery resources. 

 Sufficient depletion has been undergone to make it apparent that 

 replacement is necessary if the supply of food fish in public waters is 

 to be maintained. Such replacement is most successfully accom- 

 plished by fish-cultural means, even where the assistance rendered 

 can include only the artificial impregnation of eggs. 



During the 1931 fiscal year the numbers of commercial species 

 propagated were generally increased, although there were large de- 

 creases in the numbers of eggs handled in the case of the cod, pollock, 

 carp, and buffalofish. Under favoring weather conditions unusually 

 large numbers of pike perch, cisco, and whitefish eggs were obtained 

 in the Great Lakes region. 



PACIFIC SALMON 



Large numbers of chinook salmon ascended the streams to spawn 

 in the California and Columbia River fields. This allowed a very 

 satisfactorj'- collection of chinook salmon eggs in these sections, 

 which greatly exceeded the figures of 1930. In Puget Sound the 

 past season was an "oft'" season for the run of hump-back salmon, 

 but large numbers of eggs of this species were transferred from the 

 Alaska field in an endeavor to establish a supply of humpback salmon. 

 Total collections in all fields exceeded those of the previous fiscal 

 year. 



AFOGNAK (ALASKA) STATION 

 [Harry F. Johnston, Superintendent] 



The run of sockeye salmon into Letnik Lake began June 19 and continued until 

 August, during which time 2,649 female fish were handled and 6,347,270 eggs 

 produced. In August and September 13,671,270 eggs of the humpback salmon 

 were taken, and on reaching the eyed stage 10,155,776 of this number were for- 

 warded to the Washington State Department of Fisheries and Game. During 

 the spring 32,826 steelhead salmon eggs were collected and planted in the eyed 

 stage in Letnik River. In connection with the rearing operations 560 silver 

 salmon, salted in the previous fall, were used as a food supply. On attaining the 

 No. 1 fingerling size all sockeye salmon on hand were planted in Letnik Lake, 

 while the humpback salmon fingerlings were liberated in Letnik River. 



The year's construction work included the building of a new water tank a,nd 

 a garage. The arrangement of the latter permits the housing of the station 

 truck and tractors and leaves ample room for repair work. From 400 trees cut 

 on the station reservation sufficient lumber was prepared for the construction of 

 a dock and shipways on Letnik Bay. A new pilot house and deck and a rear- 

 ranged interior were provided for the bureau's boat Red Wing, and a complete 

 new counting weir was installed at the foot of Letnik Lake. Numerous repairs 

 of a minor nature were made to the station buildings and equipment. 



