ALASKA FISHERY AND FUR-SEAL INDUSTRIES 161 
JAPANESE SEALSKINS DELIVERED TO THE UNITED STATES 
Under the provisions of the fur-seal treaty of 1911, there were 
allotted to the United States 210 Japanese fur-seal skins, or 10 percent 
of the number taken by Japan on Robben Island in 1938. These 
skins were received by the Department’s selling agents at St. Louis, 
Mo., on May 9, 1939. 
SUBSTATION FOR SEA-OTTER PATROL 
The Bureau’s work for the furtherance of sea-otter investigations 
and patrol was continued. At the substation established on Amchitka 
Island in 1937, 4 additional overnight cabins, 8 by 10 feet, were built 
on the south side of the island at 8-mile intervals. At the camp site 
in Constantine Harbor a 10 by 16-foot powerhouse was constructed, 
and a 5-horsepower diesel engine was installed for use as a power 
plant. Two radio masts were erected on concrete bases, and radio 
antennae were strung leading to a receiving set and a transmitter. 
eee that had been erected in the previous year were given a coat 
of paint. 
The number of sea otters counted in the vicinity of Amchitka 
Island in 1938 was considerably less than the estimate for the previous 
year. Whether the difference was due to an error in the count or to 
a change in the habits and distribution of the animals was not known. 
It is anticipated that further light will be thrown upon this problem 
by investigations in succeeding years. 
COMPUTATION OF FUR SEALS, PRIBILOF ISLANDS, 1938 
By Harry J. CHRISTOFFERS 
As indicated by the commercial killings, there was a satisfactory 
increase over the previous year in the number of 3-year-old male fur 
seals arriving at the Pribilof Islands in the 1938 season. A total of 
54,140 3-year-olds were killed, compared with 50,800 in 1937 and 
54,890 in 1935. The killings for the past several years, however, do 
not show a gain commensurate with an average increase of 8 percent 
in the size of the herd. It is evident, therefore, that during recent 
years the herd has not been increasing as fast as expected, in view of 
the increases apparent for the period from 1929 to 1931. This con- 
dition is probably due in part to insufficient additions to the breeding 
reserve as a result of continuing sealing operations for several days 
after July 23. It cannot be the entire cause, however. Unknown 
factors during the life of the seals at sea must have been partly the 
cause of the large increases from 1929 to 1931, and other unknown 
factors must have caused a greater loss of life at sea during more 
recent years. Disease or natural enemies would hardly be expected 
to increase directly in proportion to the growth of the herd. It 
would not be surprising, therefore, if there should be in any year an 
abnormally large increase in the number of 3-year-old males available 
for killing. : 
The St. George Island killings this year show a remarkable increase 
over those for the past 2 years, although only slightly more than the 
number killed in 1935. 
