242 



BULLETIN OF THE BUREAU OF FISHERIES 



EXPERIMENT NO. 9.~BONNEVILLE HATCHERY, SEPTEMBER AND OCTOBER, 1921 



Eggs from: McKenzie River, 1920. 



Reared and marked at: Bonneville hatchery. 



Mark used: Removal of adipose fin and both ventral fins. 



Number marked: 50,000. 



Ldberaied: In Tanner Creek during September and October, 1921. 



Age: Approximately 13 months. 



A sample of 50 fingerlings preserved on August 24, 1921, averages 93.3 milli- 

 meters (3.7 inches) in length. The average number of rings on the scales is 13.1, 



. 43 9 

 and the average length of the anterior radius of the scales is — ^ millimeters. (See 



table 21.) An incidental check at 6 to 10 rings from the center is to be found in about 

 half of the scales (see fig. 55) ; in others (see fig. 56) there is a slight crowding of the 

 rings, which is not sufficiently pronounced to be termed a check. 



Table 21. — Chinook-salmon fingerlings marked at Bonneville hatchery August ^4, 19^1 



The returns from this experiment are represented by three 4-year-olds recovered 

 during 1924, thirty-three 5-year-olds recovered during 1925, and six 6-year-olds 

 recovered during 1926. The detailed data regarding these recoveries are given in 

 Table 22. The 5-year-old males average 31.3 inches (79.6 centimeters) in length and 

 30 pounds (13.6 kilograms) in weight. The females of that age average 34.3 inches 

 (87.1 centimeters) in length and 19.5 pounds (8.9 kilograms) in weight. The 4-year- 

 olds and 6-year-olds are represented by too few individuals to give reliable averages. 



