248 



BULLETIN OF THE BUBEAU OF FISHERIES 



The stream gi'owth shown on these scales generally is divided into two parts 

 by an incidental check, the inner of which corresponds to a similar portion observed 

 on the scales of the fingerUngs. 



The presence of the band of intermediates within the nucleus of these scales 

 indicates that the fish migrated, at least to the estuar_y, during their first year. Spring 

 chinooks normally remain in the stream for their entire first year, and it is believed 

 that the probable reason for these fish leaving fresh water before that time was 

 the unfavorable nature of conditions in Tanner Creek, where the fingerlings were 

 Uberated. It would be impossible for this small creek to support the large numbers of 

 fingerUngs that are liberated in it each year from the hatchery. Similar conditions 

 and scale peculiarities were found in experiment No. 5. Intermediate rings have 

 not been found among the other marked spring chinooks, probably because they were 

 liberated at about the end of the growing season. 



Typical scales of mature fish in their third, fourth, and fifth years are shown in 

 Figures 68, 69, and 70. 



EXPERIMENT NO. 11.— KLASKANINE HATCHERY, AUGUST, 1922 



Eggs from: Willamette River system, 1921. 

 Reared and marked at: Ivla.skanine hatcherj'. 

 Mark used: Removal of adipose fin and dorsal fin. 

 Number marked: 50,000. 



Liberated: In Klaskanine River during August, 1922. 

 Age: Approximately 10 months. 



An unselected sample of 20 fingerlings preserved on August IS, 1922, averages 



73.5 millimeters in length. The anterior radius of the scales of these fish averages 



.31 . . . 



-:j-x7r millimeters in length. The average number of rings is 9.8. All l)ut two of 



the scales have an iacidental check, which incloses 5 to 9 rings and is followed by 

 1 to 5 more widely spaced rings. The size and scale data are given in Table 25. 

 A typical scale is illustrated in Figure 71. 



Table 25. — Chinook-salmon fingerUngs marked at Klaskanine hatchery August IS, 1922 



