RESULTS OF MARKING EXPERIMENTS ON THE PRIBILG@F ISLANDS 
In follow-up studies we have learned certain things about the efficiency 
of marking operations on the fur seal. ‘Ye have also learned, through the 
medium of marked animals of knowm age, a number of facts about the biology of 
seals. In the present report we do not intend to dwell on the biological 
findings but, rather, to limit our discussion to marking experiments and their 
after effects. 
Percentages of recoveries of murked seals,-=-No one has ever been able to 
count all of the marked seals returning to the Pribilof Islands subsequent to 
a marking experiment, In the case of females, living as they do on crowded 
rookeries, it would be nearly impossible. In the case of males it could be 
done with a crew of two or three biologists devoting full time to the job, 
Thus, if every marked male seal appearing on land in its fourth summer (as a 
three-year old) were killed, painted, or sheared, a fairly complete cout could 
perhaps be made, For each of the following age-classes we present recovery 
data gleaned from past records, which, while fragmentary, are of some value, 
Yearlings,.=-Wilke and Banner watched for marked yearlings in 1941. They 
counted 1 in July, 22 in October, and 28 in November, or a total of 51 (out 
of 5,000 seals branded as pups). Of those whose sex was determined, 41 were 
males and 6 were females. Seventeen were killed for study (1941a). 
Of 5,228 pups branded in 1912 by George H. Clark, 89 were counted in the 
following autumn (Hanna 1916: 18). 
Two-year olds,-=-Palmer concentrated his attention in 1943 on the return 
of branded seals. He and Agent Daniel C. R. Benson counted 311 branded two- 
year olds, mostly males, on both islands, between July 10 and August 4 (out of 
10,000 seals branded as pups). Of these, 155 were killed. 
Three~year olds.--Likewise, Palmer and Benson in 1943 counted 766 branded 
three-year olds, of which about 500 were killed. 
~ournyear olds,--Cf the 5,047 estimated three-year olds branded in 1923, 
about one-third were counted in the following summer. Employees captured and 
sheared 1,733 of the animals between June 12 and August 5 (Bower 1925a: 149). 
Five-year olds,--Likewise, in 1925, employees sheared 1,525 estimated five- 
year olds (hone 19 
26: 149). 
Six-year olds to ten~year olds.--Of the 5,228 pups branded in 1912, 80 males 
yore: EIUied Tor setudyonhen they Teached-aece eix toctens | 
Age, years 6 7 8 9 10 Total 
Number killed 37 25 15 2 1 80 
ak, 
