ALASKA FISHERIES AND FUR INDUSTRIES, 1911. 



13 



only way to account for the difference in size would seem to be by 

 the dilferont conditions under which the eggs and fry are placed. 

 The Wood River system of lakes, of which Aleknagik is the first, 

 offers ideal conditions in extent and depth of water and abundance 

 of food for the growth of the young. The theory has been advanced 

 that the adults from fish reared in deep lakes are larger than those 

 from shallow lakes. This proposition hinges, of course, on the other 

 that salmon return at least for the greater part to the stream where 

 hatched. Throughout the season of 1911 at Lake Aleknagik from 

 the breaking up of the ice late in June until the observers left at the 

 end of July fingerlings were leaving the lake in schools. Quite a 

 number of these small fish are destroyed by birds, the Arctic tern 

 (Sterna imradisxa) being particularly destructive. These birds breed 

 in small numbers in the vicinity. 



The destructiveness of the spotted trout or charr (Salvelinus malma) 

 could be well noted at Lake Aleknagik. Numbers of these fish came 

 in with the run of salmon and could be taken on a hook by the use of 

 salmon eggs as bait. In most instances when taken during the time 

 a school of salmon fingerlings was migrating, a number, sometimes 

 as many as 15, of these were found in the trout stomachs. Of a 

 number of blackspotted trout of similar size taken under the same 

 circumstances none contained j^oung salmon. 



A rather hasty examination of the scales of a small number of red 

 salmon from the Nushagak region leads to the conclusion that the 

 greater number of the adults return at 5 years of age. The prevalent 

 belief, based largely on the Fraser River runs, is that the red salmon 

 matures in the fourth year. On this basis it has been expected that 



1912 would yield the returns from the big run of 190S. In the light 

 of later observation this seems doubtful and indicates that not until 



1913 will the new cycle begin to run. It is of the utmost importance 

 to continue the observations on Wood River until some definite 

 values are arrived at. A consideration of the catch as given in the 

 reports for a series of years does not afford much ground for deduc- 

 tions as to periodicity in the runs. It was not until about 1900 that 

 the large catches began to be made. From 1899 to 1911 the number 

 of redfish taken in Nushagak Bay is reported as foUows: 



