[fraser] PACIFIC SALMOxN 167 



returned to the sea and was caught again, a clear spawning mark 

 should be apparent on the scales." In scales of over 9,000 salmon, 

 1500 of them sockeye, I have seen no such lack of conformity as would 

 be shown by new growth appearing around the margin of the scale 

 that he figures, and yet as far as disintegration goes, this scale is good 

 as compared with many others that could readily be obtained. The 

 very absence of such strongly indicated spawning mark is one of the 

 most convincing pieces of evidence that these fish do not spawn a 

 second time. It is quite true that because no such spawning mark 

 has ever been found, it does not follow that none has ever existed and 

 consequently, all that can be said is that while it has not been proved 

 that all Pacific salmon die soon after spawning once, neither has it 

 been proved that any have long survived under ordinary conditions. 

 Certainly the great majority die, and the evidence so far obtained 

 all points to the conclusion that all of them do. 



On the other hand, there is the case of the sockeye reared in fresh 

 water, recently reported,^ in which specimens became perfectly 

 mended after spawning. 



There is not so much difference between the habits and life-history 

 of the Atlantic and the Pacific salmon as we have been led to believe, 

 since the work of later investigators, such as Hutton, Calderwood and 

 others, has shown that but a small percentage of the Atlantic salmon 

 return a second time to spawn. The work done on the Atlantic 

 salmon helps a great deal to solve some of the Pacific salmon riddles. 



Is annual spawning the primitive characteristic, from which con- 

 dition the Atlantic salmon has reached a situation where normally 

 the great majority die after the first spawning, and the Pacific salmon, 

 a situation where they all normally do, but where under certain con- 

 ditions, such as continuous life in fresh water, they may revert more 

 or less to the primitive type ? 



The five species of the genus Oncorhynchus are: 



0. tschawytscha. — Spring, king, quinnat, chinook, tyee, Columbia 

 river salmon, Sacramento salmon, with spring-jack, grilse and sea- 

 trout, used as names for the immature forms. 



0. nerka. — Sockeye, red salmon, redfish, blueback, Quinault. 



0. kisutch. — Coho, silver salmon, silverside, medium red, with 

 blueback and grilse for immature forms. 



0. gorbuscha. — Humpback, pink salmon. 



O. keta. — Dog, keta, chum. 



'Rearing Sockeye salmon in fresh water. Cont. Can. Biol for 1917, 1918, pp. 

 105-109. 



