AGE AT MATURITY OE THE PACIFIC COAST SALMON 
13 
In general, king salmon scales exhibit the same two types characteristic of the 
sockeye — a stream type, with close-ringed nuclear area, sharply set off from the envelop- 
ing wide-ringed summer band (pi. iv, fig. 7), and a sea type, of large nuclear area, with 
less crowded rings, which widen outwardly and usually pass gradually into the rings of 
the second summer (pi. vii, fig. 13). The nuclear area of the close-ringed stream type 
agrees with the entire scale' of a yearling on its seaward migration in its second spring, 
and can be safely so interpreted. The nuclear area of the sea type is here interpreted 
as in the sockeye, as indicative of an early passing to salt water on the part of those 
individuals which migrate as young fry. A more extended inquiry into this matter 
must be made before offering data with full conclusiveness, but it may be offered in 
evidence that young king salmon about 4 inches long taken in Puget Sound in mid- 
summer exhibited the wide-ringed sea type and were in their first year (pi. vii, fig. 12). 
It may also be noted that on examining a series of larger king salmon (9^ to 17^ inches 
long) taken in late summer in Puget Sound, all were found to be in their second year, 
the smaller individuals (9>2 to ii>2 inches) exhibiting the stream type of nucleus (pi. iv, 
fig. 7), and the larger members of the series (13K to i7>^ inches) the sea type (pi. vii, 
fig- 13)- 
Conspicuous in every spawning run of king salmon are the numerous undersized 
males, known locally as grilse, jack salmon, or sachems. Two theories have been held 
regarding these, according to which they have been considered either stunted individuals 
of equal age with the larger salmon, or younger fish which have matured precociously. 
The theory of precocious development has had wider currency of late, and is in entire 
agreement with the evidence from the scales, according to which the individuals are 
always in their second or third year. The mature second-year fish are smaller than 
those in their third year, and are usually little in evidence, as they escape readily through 
the meshes of the nets. None which were mature at this age have been taken by us 
in Puget Sound. But on the Columbia River, a considerable series of mature males in 
their second year, 9 to i 8}4 inches long, were secured from the seines and fish wheels. 
It will be noted that this range in size agrees with that already given for immature 
second-year fish from Puget Sound. It is further significant that in the Columbia 
River series, also, the smaller individuals, 9 and inches long, are of the stream type, 
and the larger, 13 to i8>^ inches, are of the sea type. 
The larger grilse (19 to 26 inches) are in their third year (see pi. iv, fig. 8; pi. vii, 
fig. ii), and among them, again, the smaller individuals of the series are preponderat- 
ingly fish of stream type and the larger of sea type. But in the third-year fish there is 
more overlapping of the two types, as though subsequent inequalities in growth had 
partially concealed the initial advantage secured by those which had early sought the 
sea. This is a question which merits further investigation on a much larger series than 
has thus far been examined. 
From salt water in Puget Sound we have secured immature third-year fish, both 
males and females, and also matured third-year males, taken by purse seines from the 
same school, and both feeding voraciously and equally on small sand lance and young 
60289°- — Bull. 32 — 14 2 
