58 



BULLETIN OF THE BUREAU OF FISHERIES. 



Columbia River fry and yearlings. With the exception of the three earliest collections, 

 made at hatcheries, all of the fish possess scales with rings. Very few of the wild fish 

 taken on the lower river show the marginal band of wider rings, the intermediate band, 

 which is so characteristic of the young migrants on the Columbia River. This may be 



Apr. Maif June JhIi| 

 Fru. 



Au^. Sept. Oct. 



Nov. Dec. Jan. Feb. Mch. Apr. Matj June 

 Yeo^^ing3. 



Graph 7. — Columbia River (group 4): Rate of growth , increase in number of rings, and increase 



in length of anterior radii of scales. Significance of curves is same as in graph 4, with the follow- 

 ing exceptions: a indicates collection from Little White Salmon River; h, collection from 

 McKenzie River; and "new growth" takes the place of "intermediate growth." 



accounted for by the fact that none of these collections from the Sacramento was made 

 in San Francisco Bay, which corresponds to the estuary of the Columbia, where inter- 

 mediate growth was found most commonly. The collections of yearlings made at 

 Brookdale and the majority of the collections made in the McCloud River contain 



