year. This work is being carried out in 

 cooperation with the Fisheries Research 

 Institute. Extensive scale samples and 

 length data were collected from fish taken 

 from the Kvichak, Naknek, Egegik, cind Uga- 

 shik River systems (figure 32). Samples 

 were obtained from two sources, the escape- 

 ment and the commercicil catch. In the 

 latter, the fish were taken directly from 

 conveyor belts at the canneries in the 

 •various districts, while the escapement 

 sampling was accomplished by beach seining. 



Analyses indicated that the age compo- 

 sition of red salmon differed significantly 

 in each of the Bristol Bay River systems 

 studied. The tabulation following, which 

 is based on preliminary data, shows the 

 approximate contribution of each brood year 

 to the total run. 



Figure 32. --Taking scale samples on 

 Ugashik River. 



Several projects involving basic re- 

 search on environmental factors that affect 

 survival of red salmon were continued at 

 the Brooks Lake research station (Naknek 

 River system). 



A reliable technique, using radio- 

 active tracers, was developed to determine 

 factors limiting productivity of natural 

 waters. Phytoplankton production varied 

 greatly from one lake to another, and it 

 was indicated that magnesium may be a limit- 

 ing factor in Brooks Lake. The chemical 

 effects on lake water of decomposing salmon 

 carcasses and of volcanic ash and pumice 

 were studied in 1958. The findings are 

 undergoing analyses. 



Food studies, based on two summer's 

 extensive experimental gill netting in 

 Brooks Lake, indicate that predation in 

 this lake is of minor significance in the 

 freshwater life of red salmon and also that 

 most fish, including red salmon, prefer 

 insects for food. 



Preliminary studies were begun to 

 develop a workable photographic technique 



to enumerate outmigrant red salmon in 

 Brooks River. 



Yukon River and Arctic Area 



North of Bristol Bay the only commer- 

 cial fishing cf significance is a gill net 

 fishery for king salmon, which is conducted 

 during June on the lower Yukon River. A 

 quota of 65,000 fish is the maximum catch 

 allowed by regulation and is shared by se- 

 veral small canneries and salteries. By act 

 of Congress, no other species of salmon may 

 be commercialized on the Yukon River, even 

 though large runs of chum and coho salmon 

 do occur. The aboriginal peoples of the 

 area depend upon salmon and other fish as a 

 fundamental source of food for themselves 

 and their dog teams. It is the policy of 

 the Federal Government to grant such sub- 

 sistence needs the highest priority in the 

 utilization of salmon runs along the north- 

 ern and western coasts and also in the in- 

 terior. It is for this reason that the com- 

 mercial fishery on the lower Yukon is limited 

 to a relatively small quota of king salmon. 



I 



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