FUR-SEAL INDUSTRY. 83 
CENSUS OF THE FUR-SEAL HERD. 
The policy of taking an annual census of the fur-seal herd of the 
Pribilof Islands, based on actual count of certain components of the 
herds and on estimates of others, was continued. The census was 
taken by G. Dallas Hanna, assisted by other officers of the fur-seal 
service. 
The following table shows in condensed form the components of 
the herd in 1912, 1913, 1914, and 1915, the four years which have 
ensued since the cessation of pelagic sealing: 
GENERAL COMPARISON OF RECENT CENSUSES OF THE SEAL HERD.@ 
Class of seals. 1912 1913 1914 1915 
ReACIMPDULS S ~<a =< scsccicin cine aele nis was Soe SEC eerste tie 1,358 1, 403 1,559 2,151 
ERROR GREICOW SUE ceittenn tem ne tne eek oe ois bate etuminanion toskchelns 81, 984 92, 269 93, 250 103, 527 
LGHS [eS Sa SARS RSE: Ceres 6 eeepc eeaeeae 113 105 172 673 
Young bulls (chiefly 5-year-olds)......-- 199 259 1, 658 11,271 
4-year-old bachelors...........--.-.--.-- 100 2,000 9,939 15, 848 
B-VEAI-OLGDAGHELONS oo <a e 2 ne eee 2,000 10, 000 13, 880 18, 282 
e-venteold bachelors, teibelc StL eee LU RE a) UTE a 1,000 15,000 17, 422 23,990 
enn lame DAGHlOLS...2-ci5- 205 += - tape neebeeracneras ays 3-4 13, 000 20,000 23, 068 30, 307 
Co 7 thn st AU ae IRSA 3 A A 11,000 | 15,000] 17,422 23,990 
MGAPINIPNGOWS5.=7: 3-2-2 - hoo - 12k SSE ee perd eses ee hl beld opie 13, 000 20,000 23, 067 30, 306 
TFEIRS: — = cage Se ea ee ae ET PRAT TS SS Tae ...| 81,984] 92,269 | 93,250] 103,527 
TON ke ee a ee SEY Safe aoe ds eee SE 215,738 | 268,305 | 294,687 363, 872 
aThe 1915 census is not strictly comparable to those of previous years, different percentages of death 
rate having been assumed. 
The following extract is from Mr. Hanna’s report on the fur-seal 
census in 1915: 
The census of fur seals on the Pribilof Islands in Bering Sea was taken in 1915 in 
the same manner as in the three preceding years. Bulls in charge of harems, idle 
bulls, and hauling ground seals were counted at the height of the breeding season, 
July 17 to 21. The pups, young of the year, were counted between July 27 and 
August 7. 
The basic figures of present census calculations must necessarily be the births of 
this and preceding years. By deducting from the number of births the number 
killed and the number lost from natural mortality, those classes which can not be ac- 
curately counted because not all are on land at any one time, may be estimated with a 
fair degree of accuracy. The percentage of loss from natural mortality is an unknown 
factor in the calculations and must be chosen with due regard to all conditions and 
available data. During the years when the natural losses at sea were augmented bya 
very large and uncertain pelagic catch, the percentages were estimated at 50 per cent 
loss for the first year, 15 for the second, 10 for the third, and 5 per cent each for the 
fourth and fifth years. Experience has shown that even then, these figures were very 
conservative. Since the pelagic catch has been Slneinated these percentages are 
found wholly inadequate to give a close approximation to ite actual numbers of the 
seals in the different categories. Data derived in 1915 show that the loss while the 
seals are away from the islands is nearly 50 per cent for the first three years. This 
figure is accordingly applied in the estimation of numbers of bachelors present this 
year. The lagging effects of pelagic sealing on the herd have prevented the obtaining 
of any data previous to 1915 which would warrant a change from the old percentages 
