36 
BULLETIN OF THE BUREAU OF FISHERIES 
FISH IN THEIR SIXTH YEAR, STREAM NUCLEI 
Only three specimens of this age group were found among the troll fish included 
in this study. Two of these were taken May 8 to 10, 1919, and one August 13 to 
17, 1918. In the discussion of the 6-year-old fish with ocean nuclei, it was mentioned 
that 6 years is the maximum age of chinook salmon in the Columbia River, and it 
follows that fish of this age could only be mature. The size of the eggs indicated 
1^ 
•AS 
LEGEr/D — 
• • Mature - taAen ms/de 
o Mature - ta/cen outside 
® Immature - tal(en inside 
@ Immature - taken outside 
' Single specimen 
Fig. 8. — Sizes of eggs of females in their fifth year, stream nuclei. Columbia River and the 
ocean ofi the mouth of the Columbia^ 
beyond question that such was the case. The eggs of the two specimens taken in 
May had an average log D of 0.58, and the log D of the specimen taken in August 
was 0.75. The log D of the fish of this age group taken inside the river, of which 
there were 7 specimens, ranged from 0.51 to 0.75. 
FISH IN THEIR FIFTH YEAR, STREAM NUCLEI 
Figure 8 shows the distribution of egg sizes for fish of this age group during the 
season. Only three immature fish were found. Two of these were taken in the 
