
APPENDIX D 
Age criteria for bachelor fur seals 
Early in the development of the sealing industry under United 
States Government management, it was found advisable to establish standards 
for the age and size of each animal killed, and to preserve for study 
purposes the records of those measurements. The objectives were, first, 
to impress the native clubbers with the need for care in selecting animals 
of the proper commercial size and, second, to obtain a rough age-class 
breakdown of the kill for the purpose of population computations. It was 
the practice in the late 1800's and up 1914 to age each seal killed on 
the basis of skin weight; from 1915 to 1917 on the basis of body length 
as measured by steel tape; from 1918 to the present on the basis of body 
length as measured by wooden calipers. 
Special Investigator George A. Clark conducted branding opera- 
tions on the Pribilofs in 1912. His object was to obtain precise infor- 
mation on the size and growth rate of seals of positively known age. He 
branded, as pups, 1,944 males, 1,796 females, and 1,488 of unrecorded sex. 
In subsequent years G. Dallas Hanna recovered and measured 363 branded 
seals of this series (table 18). On the basis of body measurements he 
established age-length standards for yearling and bachelor seals. 
Table 18.~-Specimens examined from the 1912 series of brandings. 

he, a A a 
Number of Length standards 
specimens established for 
Age (years Male Female males (inches) _ 
1 3 -—— up to 36-3/4 
Z 16 Zz 37 to 40-3/4 
3 120 aer 41 to 45-3/4 
4 96 --~ 46 to 51-3/4 
5 46 --- 52 to 57~-3/4 
6 37 — 58 to 63-3/4 
7 25 ee ek 
g 15 ne Be ie Ae: 
9 2 Sartre ee alae Se 
10 1 eer ee ee 
Total. .... . 361 2 
Measurements in commercial sealing statistics are now reported 
to the nearest inch. Studies of several thousand tagged animals taken 
-53- 
~ 
