PACIFIC SALMON FISHERIES. 18 
As a result of his investigations up to this point, Dr. Gilbert pre- 
sented the following conclusions drawn from the data collected: 
1. The sockeye spawns normally either in its fourth or fifth year, the king salmon 
in its fourth, fifth, sixth, or seventh year, the females of both species being preponder- 
atingly 4-year fish. 
2. The young of both sockeye and king salmon may migrate seaward shortly after 
hatching, or may reside in fresh water until their second spring. Those of the first type 
grow more rapidly than the second, but are subject to greater dangers and develop 
proportionately fewer adults. 
3. Cohosalmon spawn normally only in their third year. The young migrate either as 
fry or yearlings, but adults are developed almost exclusively from those which migrate 
as yearlings. 
4. Dog salmon mature normally either in their third, fourth, or fifth years, the 
humpback always in their second year. The young of both species pass to sea as soon 
as they are free swimming. 
5. The term “grilse,’’ as used for Pacific salmon, signifies conspicuously undersized 
fish which sparingly accompany the spawning run. They are precociously developed 
in advance of the normal spawning period of the species. So far as known, the grilse 
of the king salmon, coho, and dog salmon are exclusively males; of the sockeye, almost 
exclusively males, except in the Columbia River, where both sexes are about equally 
represented. The larger grilse meet or overlap in size the smaller of those individuals 
which mature one year later at the normal period. 
6. Grilse of the sockeye are in their third year, of the king salmon in their second 
or third year, of the coho and the dog salmon in their second year. 
7. The great differences in size among individuals of a species observed in the 
spawning run are closely correlated with age, the younger fish averaging constantly 
smaller than those one year older, though the curves of the two may overlap.4 
Since 1910 Dr. Gilbert has devoted much of his time to investiga- 
tions’ along this line, especially on the sockeye, with most interesting 
and einai. results. 
His observations on the sockeye runs of British Columbia indicate 
that they consist principally of four and five year fish and that these 
two classes appear during successive seasons in widely differmg pro- 
portions; that each stream has its distinctive race of sockeye, the 
rogeny returning at maturity to the parent stream; that sockeye 
ry rarely survive when they proceed to sea within the year in which 
they are hatched; and that sea feeding, with the consequent rapid 
growth, is the most important factor in producing early maturity, 
an equal number of years in fresh water producing conpanaunels 
little effect. 
MARKING SALMON. 
A favorite recreation for quite a number of Pacific coast people has 
been the marking of salmon fry in order to find out the age at which 
they return to spawn, the rate of growth, etc. Scattered through 
the reports of the various State fish commissions, and occasionally 
in the reports of the United States Bureau of Fisheries, are to be found 
detailed reports of such markings and the sometimes remarkable 
a Age at Maturity of the Pacific Coast Salmon of the Genus Oncorhynchus. By Charles H. Gilbert. 
Bulletin, U. S. Bureau of Fisheries, 1912, Vol. aT peat 22. Washington, 1913. 
+ Contributions to the Life History of the Sockeye Salmon. (No. 1.) By C. H. Gilbert. Report of 
British Columbia Commissioner of Fisheries for the year ending Dec. 31, 1913, with Appendices, pp. R53-78. 
Contributions to the Life History of the Sockeye Salmon. (No. 2.) By C. H. Gilbert. Report British 
Columbia Commissioner o! Fisheries for the year ending Dec. 31, 1914, wi oe pp. N45-75. Con- 
tributions to the Life History of the Sockeye Salmon. (No. 3.) By C. H. Gilbert. Report British 
Columbia Commissioner of Fisheries for the year ending Dec. 31, 1915, with A ae, PP. 27-64, 6 pls. 
Contributions to the Life History of the Sockeye Salmon. (No. 4.) By C. H. Gilbert. eport British 
Columbia Commissioner of Fisheries for the year ending Dec. 31, 1917, with epee: pp. Q33-80, 14 pls. 
Contributions to the Life History of the Sockeye Salmon. (No. 5.) By C. H. Gilbert. Report British 
Columbia Commissioner of Fisheries for the year ending Dec. 31, 1918, with pep nies pp. X26-52, 24 pls. 
Contributions to the Life History of the Sockeye Salmon. (No. 6.) By C. H. Gilbert. Report, British 
Columbia Commissioner of Fisheries for the year ending Dec. 31, 1919, with Appeneices, pp. U35-68, 6 pls. 
Victoria, British Columbia. 
