SALMON AND SALMON FISHERIES OF SWIFTSURE BANK 
755 
From scale reading (Clemens, 1934) it appears that approximately 91 percent of the 
returning adults had left the lakes in their second year, 5 percent in their third year, 
and 4 percent in their first year. Foerster (1929b, 1934) shows that from the 1925 
spawning at Cultus Lake, 6.2 percent of the migrants were in their first year (fry), 
92.9 percent were in their second year (yearlings) and 0.9 percent were in their third 
year. 
AGE AT MATURITY 
The majority of the sockeyes of this region reach maturity and return from the 
ocean to their spawning grounds in their fourth summer. From 1920-33, inclusive, 
a period of 14 years, the ages of the sockeyes taken by the traps near Sooke, on Van- 
couver Island, (Clemens, 1934) have averaged as follows: 3-year-olds, 3.2 percent; 
4-year-olds, 76.4 percent; 5-year-olds, 19.6 percent; and 6-year-olds, 0.6 percent. 
Since the proportion of the fish at each age varied considerably in different parts of 
the season, these figures are only an approximation of the number of fish at each age 
composing the catch, but they show the preponderance of 4-year-olds. 
The cycle, or generation of sockeyes occurring quadrennially in the year following 
leap year (1909, 1913, 1917, etc.) was, as is shown below, tremendously abundant up 
to 1913, and fairly abundant in 1917, but much less abundant in 1921 and later years. 
Cilbert (1914) showed that the sockeyes running in 1913 were 99.5 percent 4-year-olds. 
In 1917 they were 94 percent 4-year-olds. In the past 4 years of this cycle (Clemens 
1934) they have averaged but 77.4 percent 4-year-olds. 
There is reason to believe that the change in the proportion of sockeyes 4 and 5 
years of age is caused, at least in part, by changes in the proportion of the runs coming 
from different lake systems. This was pointed out by Gilbert (1917), who said that 
the runs to the various tributaries did not show the same proportions of 4- and 5-year- 
olds as did the samples of the run as a whole, the 5-year-olds being especially prominent 
in many localities below Hell’s Gate. 
During May and early June a run of sockeyes occurs that contains a large propor- 
tion of 5-year-old fish. This run is too small to be of any importance, as can readily 
be seen from the trap curve of seasonal occurrence (fig. 11), and is distinguished by 
the small size of the individuals, the lack of oil, and light-colored flesh. Since these 
fish lose most of their color in the canning process, they are usually sold as cohos. 
Some of these very early sockeyes may be Skagit River fish, which are taken in 
late June along West Beach, but the larger part are probably bound for the Fraser 
River, as the traps in Rosario Strait, Lummi Island, Boundary Bay, and Point Roberts 
Areas all take them, and in about the same amount as the traps in the Salmon Banks 
and South Lopez Areas. 
A third group of sockeyes that merit attention are the “grilse.” These fish, 
usually males, have migrated to the ocean at the usual time, in the second year, but 
have matured precociously, returning after only 1 year in the sea, instead of the 
customary 2 years. On the years that preceded the former big years grilse were always 
numerous. Gilbert (1913, 1916) estimated them at 21.5 percent of the run in 1912, 
and 10 percent in 1916. The presence of these small sockeyes on such years was well- 
known to the cannerymen. On years preceding the off years the percentage of grilse 
in the run was quite small ; very often negligible. 
71941— 3S 5 
