74 
BULLETIN OF THE BUREAU OF FISHERIES 
their racial status. Samples of the scales of each sal m on had been taken when the 
tag was attached. It remained to group these samples in accordance with the 
streams in which the salmon were captured and to compare the characteristics of 
the groups thus formed. In localities where few recaptures were reported, as in 
Cook Inlet, Karluk, Alitak, Chignik, and others, the material was not adequate 
for such a study; but in all the rivers of Bristol Bay and in certain red-salmon 
streams along the southern shores of the Peninsula, in its western portion, con- 
siderable numbers of tagged salmon were captured. In all these cases examina- 
tion of the scales affords conclusive evidence that the fish were returning to the 
streams in which they were spawned, and that they manifested the characteristics 
of the colonies of their native streams. 
It is not to be overlooked that the data afforded by our experiment were of 
necessity very incomplete for a determination of racial differences. Such differ- 
ences include many characteristics — as average size, color, and richness of flesh — 
which were unavailable to us. The only data afforded by the scales were associated 
with methods of growth, ages at maturity, amount of growth, and length of sojourn 
in fresh water, and other minor characteristics of development which can record 
themselves on the growing scale. 
The most tangible of these consist in the proportions in which different year 
classes occur in the runs. Two streams in close proximity at their mouths often 
differ widely in this respect. The Nushagak and the Kvichak colonies furnish 
a well-marked example. As we have learned from previous examination of these 
races, a considerable percentage of the Nushagak fingerlings always descend to 
the sea when but 1 year old, and they mature and return to spawn at the age of 
4 or 5 years. On the other hand, the Kvichak fingerlings are practically all 2 or 3 
years old when they enter salt water, and they mature mostly at the age of 6 or 7 
years. If the tagged fish recovered in the Nushagak had failed to register such a 
difference in early growth and total age as compared with the tagged fish recovered 
in the near-by Kvichak, we should have grounds for doubting in their case the 
operation of the homing instinct; but an examination of Table 43 indicates clearly 
the existence of these differences. 
Table 43. — ■ Percentages of the different year classes among tagged red salmon recaptured in different 
streams of the Alaska Peninsula and. Bristol Bay 
South side Alaska Peninsula 
Bristol Bay 
Year classes 
Pavlof 
and 
Volcano 
Bays 
Cold 
Bay 
Thin 
Point 
Mor- 
zhovoi 
Lake 
Ugashik 
Egegik 
Naknek 
Kvichak 
Nusha- 
gak 
One year in lake: 
9 
25 
72 
7 
66 
1 
2 
4 
52 
75 
31 
8 
1 
5 
2 
54 
4 
Two years in lake: 
22 
2 
3 
67 
37 
54 
57 
30 
17 
3 
11 
17 
46 
35 
27 
12 
Three years in lake: 
1 
8 
8 
3 
12 
8 
2 
Total 
100 
100 
100 
100 
100 
100 
100 
100 
100 
