GROWTH AND MATURITY OF SALMON IN THE OCEAN 
37 
lower part of the Columbia River estuary, May 17 and 18, 1920, one in a trap in 
Baker Bay, and another by gill net. The other immature fish was taken by troll, 
June 4, 1919, The figure shows how distinctly these immature specimens are 
separated from the maturing fish on the basis of egg size. There can be no doubt 
of their immaturity. Figure 38 shows a scale of one of the immature fish taken 
inside the river in May, and Figure 39 one from a mature fish of the same age 
group taken at the same time. 
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Fig. 9.— Sizes of eggs of females in their fourth year, stream nuclei. Columbia River and the 
ocean oil the mouth of the Columbia 
FISH IN THEIR FOURTH YEAR, STREAM NUCLEI 
The disti'ibution of egg sizes found among the females of this age group are 
shown in Figure 9. Two distinct groups are apparent, in one of which the average 
log D is less than 0.30. In the other group, the log I) ranges from 0.40 or 0.50 in 
the early part of the season and to about 0.80 at the end of the season. The first 
group is composed of immature individuals and the second of those that are matur- 
