10 ALASKA FISHERIES AND FUR INDUSTRIES, 1911. 



of growth are marked by the distribution of lines on the scale some- 

 what as in the growth of rings of trees, and these appear to furnish 

 an almost infallible index to the life of the fish. It is now known 

 that not all of a species mature at the same age, but the proportion 

 that are normal greatly overbalances the remainder. A more com- 

 plete stud}'^ of the age problem may throw light on the runs of under- 

 sized fish in such streams as the one at Necker Bay. It has been 

 found in the study of the salmon of Norway that it matures later 

 in northern waters than in southern. It is not improbable that a 

 similar condition obtains in the Alaska salmon ; and even if the nor- 

 mal age of the Fraser River sockeye is 4 years, that of the Alaska 

 sockeye may be 5. This ability to determine the age of any par- 

 ticular fish will be of incalculable value in checking the results of 

 marking experiments. 



It is to be deplored that no definite data have ever been acquired 

 as to the effectiveness of natural spawning. This, with the "parent 

 stream" proposition, is the crucial point in the salmon question. 

 It is true that this effectiveness must vary as widely as do the con- 

 ditions under which the spawning is done, but a series of careful 

 tests would determine what the normal output should be under any 

 given conditions. It is not improbable that a general undervalua- 

 tion of natural productivity and a corresponding overestimate of the 

 results to be expected from hatchery work is responsible for the 

 one time widely diffused belief that the presence of a few hatch- 

 eries would cure all the ills of an unremitting pursuit of salmon; 

 while, now that the few hatcheries in operation do not seem to accom- 

 pUsh this miracle, the opposite tendency to decry all hatchery work 

 is supplanting the former extreme optimism. 



The hatchery can cover but one period of danger to the fish — 

 that between the extrusion of the egg from the mother fish and 

 the entrance of the fingerUng upon its struggle for existence. In 

 all its subsequent career it is at the most on a par with its naturally 

 produced neighbor, granting it is equally as capable. That hatch- 

 eries alone can not substitute for overfishing, destruction of spawn- 

 ing beds, deforestation, and pollution of waters is shown by the 

 experience with the Atlantic salmon. However many hatcheries 

 may be estabHshed, adequate hmitations on the fishery and pro- 

 tection of natural production must be conjoined. Whether a cer- 

 tain curtailment of the number of spawners allowed to reach the 

 beds is advantageous is yet unanswered. Nature has her own 

 checks to prevent dominance of certain species, and the loss on 

 the spawning beds due to overpopulation may be one of these. 

 Admitting that a fraction only of the adult fish is sufficient to con- 

 tinue the supply, the question arises, Which fraction ? Shall the 

 early run, or the late run, or a distributed run effected by weekly 



