GROWTH AND MATURITY OF SALMON IN TTIE OCEAN 
35 
FISH IN THEIR SECOND YEAR, OCEAN NUCLEI 
All of the females of this age group taken in the ocean have been found to be 
immature. This was to be expected, since it is known that no mature females of 
this age are found among the spawning runs within the river. Figure 7 shows the 
distribution of egg sizes during the season. Comparison with Figure 6, which shows 
the size of eggs of the 3-year fish with ocean nuclei, will show that the eggs are dis- 
tinctly smaller in the case of the 2-year-old fish. This would be expected from the 
fact, previously demonstrated, that the size of the eggs is correlated to a high degree 
with the size of the fish. 
The question arises as to the relative maturity of these 2-y ear-old fish as compared 
to those that are 3 years old. It has been shown above that the method used for 
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Fig. 7. — Sizes of eggs of females in their second year, ocean nuclei. Columbia River and the 
ocean off the mouth of the Columbia 
determining relative maturity is inadequate to differentiate between degrees of 
immaturity, although it is, in most cases, an entirely adequate and reliable means 
for distinguishing between fish that will mature during the year in which they are 
taken and those that will not mature for at least one more year. Although it is 
impossible to establish the fact with certainty, the probabilities are all in favor of 
considering the 2-year fish as, on the whole, one year further from maturity than 
the 3-year fish taken at the same time. Certain obvious possibilities for error are 
inherent in such a treatment, especially when comparatively few data are available, 
as in the present case, but it is felt that the picture presented by this means will be 
much nearer the true state of affairs than can be arrived at by any other method. 
This allowance will, therefore, be made in the later discussion of the percentages 
of mature and immature fish taken at different times of the year. 
