SEAWARD MIGRATION OF CHINOOK SALMON. 



27 



Six young chinooks were taken at Astoria, Oreg., November 7, 1914. These were 

 captured by hook and line from under the Union Fishermens' Cooperative Cannery. 

 Nothing of particular interest appeared in the study of this small collection, and the table 

 (20) is therefoi'e presented without comment. 



Table 20. — Young Chinooks from Astoria, Oreg., Nov. 



1914. 



November 19, 1915, seven small chinooks were collected by means of a seine on a 

 small sand bar near Warrendale, Oreg. (See Table 21.) This is on the Columbia River 

 about 40 miles above the point where the Willamette River joins the Columbia. These 

 fish average only 93 mm. in length, and it is worthy of note that the scales show no 

 indication of the beginning of a period of rapid growth. The scales of one specimen 

 show a primary check four rings from the center of the scales. Four specimens show the 

 narrow, winter rings at the margins of the scales. The other three specimens have scales 

 whose marginal rings are still of the summer type, no narrowing being apparent. 



Table 21. — Young Chinooks from Warrendale, Oreg., Nov. ig, 1915. 



Scales were taken December 4, 1914, from 52 specimens of young chinooks which had 

 been reared at the hatchery of the U. S. Bureau of Fisheries at Clackamas, Oreg. These 

 fish were measured but not sexed. The scales of these are no exception to the rule that 

 the scales of hatchery fish exhibit uneven and abnormal growth and are seldom of much 

 value in scale study. Since these are fish of known age, having been reared from eggs 

 which were spavmed in the fall of 1913, it will, however, be interesting to make a com- 

 parison between them and wild fish of the same approximate age. These hatchery fish 

 are quite irregular in their growth, so much so, in fact, as to indicate a bimodal curve. 

 The average length is, however, about the same as the average of other collections made 

 at the same time of year, being less than some and greater than others. The scale growth 

 is also, in spite of its irregularities, quite comparable with that observed in the wild fish 

 in the number and the general arrangement of the rings. The data regarding these fish 

 are collected in the following table (22) . 



