GROWTH AND MATURITY OF SALMON IN THE OCEAN 
45 
with ocean nuclei, even thougli th.e two types are predominant for approximately 
equal times. 
Among the fish with stream nuclei, those in their fourth and fifth years are most 
common. A few in their sixth year are taken, but constitute a relatively small 
part of the total catch. Three-year-old fish are quite common, but this age group 
contains only precociously mature males. Two-year-old fish with stream nuclei 
are very rarely found. 
The fish wdth ocean nuclei are likewise predominantly 4 and 5 years old. Fish 
in their sixth year are comparatively rare, but those in their third and second years 
are fairly common, especially during the last half of the season. It has been shown 
I 
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Fig. 12— Percentage of fish with stream nuclei taken inside 
above that some of the 3-year fish with ocean nuclei are mature females, but most 
of the fish of this age group are males, and all of those in their second year are the 
precociously mature males locally knovv'n as "grilse" or "jack salmon." 
The variations in the percentages of fish of the different age groups found among 
the fish taken in the ocean is strikingly different from those observed among the 
fish taken inside the river. The data are presented in Table 10 and Figure 13. 
The trends shown on the graph represent the position of the averages given at the 
bottom of the last two columns in Table 10. In view of the fact that there were 
no consistent changes in the percentages of fish wdth ocean and with stream nuclei, 
it appeared that the averages would represent the trends as accurately as could 
be done by any other means. 
3210°— 2ot 3 
