KARLUK RIVER RED-SALMON INVESTIGATION 



31 



the fry in question have had this origin and that they occur numerously. If this is 

 true, their mortality in the sea must be extraordinarily great, for there are relatively 

 few mature fish returning to spawn that have had this early history. In the 1926 

 run of mature fish only six-tenths of 1 per cent belonged to this group, which passes 

 out to sea in the early fry stage before the formation of the scales, and the adult 

 scales of which do not, therefore, record any growth in fresh water. 



The seaward migration of Karluk fingerlings is a notable sight. At the mouth 

 of the river they are first observed late in May, the wave of migration reaching its 

 height and commencing to recede during the first two weeks of June. Where they 

 first encounter brackish water (in the lagoon at the mouth) they are seen on every 

 side leaping high in the air, with flashes of silver, rehearsing in miniature the leaping 

 habit of the adults when they first taste fresh water on their return from sea at time 

 of spawning. 



At the time of their downward migration the Karluk fingerlings are unusually 

 large and form a sturdy stock. They can well be expected to give a good account 

 of themselves during their life at sea and should escape their enemies in larger measure 

 than do the smaller fingerlings of many other streams. Their large size is partly 

 due to their long residence in Karluk Lake, partly, no doubt, to the unusually favor- 

 able conditions for growth which they find in this watershed, and partly, perhaps, 

 to a racial habit of vigorous growth, which they may possess independent of external 

 conditions. In so far as their large size and consequent high survival value is deter- 

 mined by length of residence in fresh water, these desirable qualities may have been 

 dearly bought, for it is an open question whether the serious reduction in numbers 

 that must accompany an additional year or two of residence in fresh water may 

 not outweigh the advantages that the survivors experience through increase in size. 

 Those who have seen the hordes of trout and other predatory forms that infest river 

 and lake and daily take their tremendous toll of young salmon during the entire 

 period of their life in fresh water find it difficult to believe that mortality during 

 this period is less than it would have been if spent in the sea. Sea life certainly has 

 the advantage of inducing more rapid growth, with the result that the relatively 

 defenseless stages are passed through more rapidly. We can be sure that a racial 

 habit of migrating seaward predominately in the spring of the second year instead 

 of during the third and fourth years, as at present, would produce vastly larger 

 schools, consisting of migrants of smaller size. What the net results would be, com- 

 pared with the present procedure, we have no facts to determine, but we look hope- 

 fully to the results of further investigations along the lines now planned. The 

 Chignik fingerlings are much smaller when they seek the sea than are those of the 

 Karluk race. If we can succeed in estimating the numbers of downstream migrants 

 in the Karluk and Chignik Rivers over a term of years and can establish the average 

 proportion of each that returns at maturity, we shall have important evidence 

 bearing on this problem. 



The problem itself is of more than academic interest, and in a modified form pos- 

 sesses great practical importance. More and more, in recent years, the salmon hatch- 

 eries have employed their funds in increasing their pond capacity and in feeding and 

 rearing the young to larger sizes before liberation. It is a moot question whether 

 funds thus employed produce larger net results than they would produce if used to 



