658 
BULLETIN OE THE BUREAU OF FISHERIES 
an escapement of 30,000 and at Silver Salmon Bay, 5,000; thus bringing the total 
escapement for the respective years to 920,089 and 620,568, and the total known 
run of reds to 1,243,685 in 1926 and 892,737 in 1927. 
The general trend of the red-salmon catch at Alitak is shown in Figure 5 and 
was determined by a moving average by fives. It is seen that the catches were 
above average for a considerable period between 1895 and 1908, were relatively 
low from 1908 to 1915, and then were high again until about 1923. Beginning 
with 1924 the catches have been materially affected by the regulations and the 
records can not be considered as comparable with those of earlier years. Extraordi- 
nary catches were made in both 1917 and 1921 — -catches that were considerably higher 
than any recorded before or since. So far as we can determine there was no material 
change in the intensity of fishing during this period, and it seems safe to conclude that 
the runs were unusually large in these years. The fluctuations of the trend, or 
long-time movement, do not clearly indicate depletion although the reduced catches 
in recent years may be due in part to this condition. It can not be said, however, 
that there are definite evidences of depletion shown by these data since the shift 
in the nature of the fishery that 
has occurred since 1914 may have 
obscured any change in general 
abundance that has taken place. 
The cyclical or short-time 
changesare very irregular at Alitak as 
is shown by Figure 6, which shows the 
yearly fluctuations about the trend 
as a percentage of the trend. The 
coefficients of correlation in the 
cyclical fluctuations at 4 and 5 year 
intervals have been calculated and 
found to be statistically insignificant. 
(See Part I, p. 62, for a discussion 
of this procedure.) Inspection of the data showed also that there was no significant 
correlation at 6-year intervals, although the coefficient was not calculated. The value 
of “r” for the 4-year interval was +0.247 ± 0.119, and for the 5-year interval +0.204 
±0.124. It is evident that there are no clear-cut cycles of abundance in the Alitak 
red salmon such as have been demonstrated for the Bristol Bay and Karluk fish. 
This is presumably due, as at Chignik, to the fact that the fish are not so predomi- 
nantly of a single age group. Observations made by the late Dr. C. H. Gilbert 
showed wide fluctuations in the abundance of different age groups at different times 
during the season of 1914. The predominant age during the latter part of the season 
was 5 years, but earlier in the season 6-year and even 7-year fish were very common. 
Since these observations cover only the one year, and that some time ago, they can 
not be considered as certainly typical of the runs of this district, but the presence of 
relatively large percentages of at least two age groups indicates that this condition 
may be the cause of the lack of correlation in the catches at definite intervals. 
OTHER SPECIES 
Previous to 1909 the catch of species other than reds was confined to occasional 
years in which a few cohos were taken. Beginning in 1909 and continuing through 
1927, catches of coho, chum, and pink salmon, particularly the latter, were regularly 
Figure 6. — Percentage fluctuation from the trend of the catch of red 
salmon at Alitak 
