CHINOOK S.\IiMON MARKING, COLUMBIA RIVER 



227 



Table (.1. — Chinook salmon marked at Bonneville hatchery during the fall of 1910, when approximately 

 12 months old, and recovered diiring the season of 1920 



• The records accompanying these two specimens were confused, so that it was impossible to tell which specimen weighed 16 

 pounds and which 21 pounds. 



' The data here are not exact, as the fish had been cleaned before the data were taken. 

 » The ejcessive weight given for this individual is undoubtedly an error. 



The examination of the scales of these marked adults has shown, as would be 

 e.xpected from then- known history, that the nuclei are all of the "stream" type, and 

 that there are invariably three complete years of ocean growth and usually a mar- 

 ginal band of wider rings representing the beginning of the fourth year in the ocean — 

 the fifth in the life of the fish. (See figs. 22, 24, 26, and 28.) 



Particular interest attaches to the examination of the nuclear portions of the 

 scales of these fish on account of the light they throw on the interpretation of scales 

 from unmarked fish. The chief difficulties in the interpretation of the scales of 

 chinook salmon are those associated with the growth of the first year, and positive 

 information as to the significance of various phenomena, such as is obtainable from 

 marked fish, is especially desirable. The nuclei of the scales of these fish consist 

 in a central portion of true stream growth, which is usually surrounded by a more 



