CHINOOK SALMON MARKING, COLUMBIA RIVER 



255 



Table 31.— Chinook salmon marked at Big White Salmon River hatchery during the spring of 1923, 

 when approximately 8 months old, and recovered during the seasons of 1924, 1925, and 1926 



These nuclei are complicated further by the presence of an incidental check in 

 the second year. This check may be seen in Figure 78. In this case the check is 

 not sufficiently pronounced to cause any trouble. Ordinarily it causes no trouble 

 in so far as age determination is concerned, but it may lead to some question as to 

 what point on the scale represents the end of the first year's growth. This is espe- 

 cially true where the nucleus is poorly differentiated. The scale shown in Figures 

 79 and 80 gives difficulty on this score. If the check at 39 rings is the winter check, 

 this nucleus is among the largest in the collection, the second summer band is e.x- 

 tremely narrow, and the usual incidental check in the second year is absent. If, 

 however, the check at 23 rings is the first winter check, the nucleus falls at the lower 

 end of the range of size and the usual check formed at the time of liberation is lacking; 

 but the second summer band, with its incidental check, is typical of this collection. 

 The latter explanation appears to be the more logical. 



Figures 81, 78, and 75 illustrate scales of fish that matured in their second, 

 third, and fourth years, respectively, 



