Photo from Dr. H. :M. Smith 
SIGNING SPAWNING SALMON IN THE SACRAMENTO RIVER, IN CONNECTION WITH 
A HATCHERY. 
perishes after a few hours' existence, and 
in the annual plants. We can only say 
of such that they have served their pur- 
pose and are no longer needed. 
The death habit of the salmons was 
doubtless developed to prevent the over- 
stocking of streams, the exhaustion of 
the food supply of the young while in 
fresh water, and the consequent danger 
of the wiping out of species by mere ex- 
cess of numbers. This wise precaution 
of nature has become a positive detri- 
ment by the appearance of the human 
factor on the scene and the resulting de- 
struction of a large proportion of the 
run of each species each year in prac- 
tically every stream before the spawning 
act has occurred. 
PERIODICITY OF THE RUNS 
While the Pacific salmons run with 
more or less regularity, year after year, 
two of the species exhibit, in particular 
streams or regions, a marked periodicity 
in abundance which is so well established 
that it can be predicted with certainty 
years in advance. 
The blueback, or sockeye, in certain 
streams shows a climax in abundance 
every fourth year. This is especially 
marked in Puget Sound and Fraser 
River, where the years 1905 and 1909, 
for example, were characterized by im- 
mense runs, while in 1906 and 1910 the 
abundance, as shown by the catch, was 
only one-fourth or one-fifth as great. 
The quadrennial periodicity in Puget 
Sound is strikingly shown by the fish 
caught and canned during the years 1903 
to 1910, as follows : 
1903 167,21 1 cases 
1904 109,264 
1905 825,453 " 
1906 178,748 " 
1907 93,122 " 
1908 170,951 " 
1909 1,09/, 904 " 
1910 248,014 " 
The case of the humpback salmon in 
the Puget Sound region is perhaps the 
best marked example of periodicity. The 
species there is biennial in its appearance. 
One year it comes in incalculable num- 
bers, crowding the streams, filling the 
499 
