94 ALASKA FISHERIES AND FUR INDUSTRIES IN 1915. 
of the 100 known 3-year-old males killed in 1915 had skins weighing 5? pounds or less. 
This weight has been the division point of the 2-year-old and 3-year-old classes. Any 
computations based upon a premise involving such a margin of error should not be 
seriously considered. The skin of any seal weighs according to the fleshiness of the 
animal, the sharpness of the skinner’s knife, the time of day, the condition of the 
weather, and the personality of the Aleut who takes it off. The skin of a small seal 
may therefore be heavy and a large one may be light. 
The total births in 1913 were 92,269. Deduct 35 per cent for loss the first year and 
there remained 59,975 yearlings in 1914. Deduct 20 per cent for loss the second 
year and there remain 47,980 2-year-olds of both sexes in 1915. Half of these should 
be males and half females, or 23,990 of each sex. 
Three-year-old males.—This is the class from which skins are taken at present. It 
was formerly thought that the individuals of this class were uniform in size and skin 
weights, but the figures obtained in 1915 show conclusively that there is a great amount 
of variation. Only 16 seals are known to have been killed from this class in 1914, 
the branded 2-year-olds. Consequently these only can be deducted. 
The number of the class at the close of the killing season, August 10, 1915, is shown 
as follows: Deduct from 81,984, the number of pups born in 1912, 35 per cent for 
loss the first year and there remained 53,290 yearlings in 1913. Of these, half should 
be females, leaving 26,645 males. Five of these were killed in 1913, which leaves 
26,640. Deduct 20 per cent from this for loss the second year and there are 21,312 
2-year-old males at the beginning of the 1914 season. Sixteen of these were known 
to have been killed, leaving 21,296 at the close of the 1914 season. 
Of the 21,296 2-year-old males at the close of the 1914 season, 4 per cent should 
have been the loss at sea. This leaves 20,444 3-year-old males at the beginning of 
the 1915 season; 1,168 of these were killed on St. Paul Island and 994 on St. George 
Island prior to August 10, leaving 18,282 as the number which still exist. 
Of the 26,645 yearling females in 1913, 20 per cent should have been lost the second 
year, leaving 21,316 2-year-olds to be impregnated in 1914. Allowing 4 per cent loss 
the third year leaves 20,463 females which should have gone into the breeding cov 
class in 1915. The number which actually gave birth to pups in 1915 is found by 
deducting 10 per cent from the 93,250 breeding cows of 1914 for loss due to old age, 
and subtracting the remainder, 83,925, from the known number of breeding cows in 
1915, 103,527, leaves 19,602, which is so close to the 20,463 that the difference is 
negligible. 
Four-year-old males.—Many of the smaller ones of this class intergrade in size with 
the larger 3-year-olds. Since the animals were born in 1911 they have not been sub- 
jected to pelagic sealing and the losses of 35, 20, and 4 per cent should be applied to 
them. The loss at sea after the third year and up to the twelfth seems to be so small 
that it is negligible. 
The births in 1911 as determined by the 1914 investigation® were 75,000. After 
deducting 35 per cent loss for the first year and 20 per cent for the second year, there 
remained 39,000 2-year-olds in 1913. Half of these should have been males and half 
females. The latter have gone into the breeding-cow class and of the 19,500 males, 4 
per cent should have been the loss the third year, leaving 18,720 3-year-olds at the be- 
ginning of the 1914 season. Of these 1,901 were killed on St. Paul Island and 971 
on St. George Island, leaving 15,848 as the number of 4-year-old males in the herd in 
1915. Itis safe to assume that only a negligible number of them were killed as 2-year- 
olds in 1913 and as 4-year-olds in 1915. It is not possible to get a close approximation 
to the exact number from the published skin weights. The 1914 investigation assumed 
a maximum skin weight of 5? pounds for 2-year-olds and the same for a minimum for 
the 3-year-olds and on this basis deducted 515 from this class as having been killed in 
1913 as 2-year-olds. Data obtained in 1915 show that such a division can not be made, 
« Bureau of Fisheries document no, 820, p. 35. 
