68 



FISH AND GAME COMMISSION. 



show US clearly that our salmon of the Sacramento are well on the road 

 to commercial extinction. Salmon investigations have been carried on 

 for the purpose of determining what protective measures should be 

 adopted in cutting down the commercial catch. Another, secondary 

 ob.ject of the investigations is to gain information which will throw 

 light on the methods employed in artificial propagation : more especially 

 on the question of when and where the young salmon should be liberated. 

 The salmon investigations are in charge of Prof. J. 0. Snyder of 

 Stanford University. He has one full-time assistant, ]\Ir. E. A. 

 McGregor, and has employed one other assistant during the summers. 



Fig. 21. Photomicrograph of scale of salmon marked at the Mount Shasta Hatchery 

 in 1917 and talten at Monterey, April 6. 1920. Length 73 centimeters. Numerals 

 marlc the end of the first, second and tliird years of growth. 



]\Iuch "work has been done in gathering data and material at the 

 several salmon fi.shing centers. ]\Iuch of the material has yet to be 

 studied and anatyzed. This material has at all times been gathered so 

 that as far as possible it was representative of the commercial catch. 

 An age analysis has been made of each season's catch through a study 

 of the scale samples which have been systematically taken. This know- 

 ledge will be of invaluable assistance in devising closed seasons for 

 the different sea trolling districts for the purpose of minimizing the 

 catch of immature salmon. 



It was hoped that through a study of the samples of scales collected 

 it would eventually be possible to identify the salmon of any stream when 



