No official figures are available for the total number of seale Killed off Japan 
during this season. However, from the number of potential seal-catching vessels in oper- 
ation and their estimated average catches (p 45), the 1948-49 illegal kill is believed to 
have been between 2,000 and 3,000 animals, an estimate which is supported by the amount of 
fur seal on sale in the local markets (p 45). The 1,200 Pribilof seals assumed to have 
been killed this past season therefore represent about one-half the estimated total kill 
and suggest that Pribilof seale comprise at least one-half the animale wintering off Japan. 
Referring back to the assumption of 100,000 animale contributed by the Asiatic rookseries, 
the total wintering population in Japanese watere thus becomes roughly 200,000 or more. 
A certain amount of wandering, particularly on the wintering grounds, is denon 
atrable in all migratory species. Therefore, it is reasonable biologically to postulate 
that about 100,000 seale swim westward to Japan from the Pribilofs each year instead of 
eastward to Horth American waters as the main herd is known to do. A conditioned nucleus 
of the same individuals probably follows this westward route year after year and may well 
be discovered in the future to occupy one particular section of the Pribilof breeding 
grounds. However, this segment is so small, less than five percent of the total Pribilof 
population, that it might aleo be considered the result of normal accidental straying. 
The authors’ extremely reluctant and tentative estimate of 200,000 seale currently 
wintering off Japan ie still only a guess, although the most probable figure on the basis 
of the secant evidence available. It ie within the outside limite established by the sample 
densities observed, and in accord with the probable breeding ground contributions. But it 
ie still a guess, based on assumption after assumption, each of which i& sudject to a wide 
degree of error. The authors are well aware that compounding assumptions multiplies in- 
stead of cancels their respective degrees of error. Nevertheless, this is as close to the 
truth as a guess can come until more reliable statistics are gathered. At least it gives 
an idea as to the order of magnitude of the wintering population. 
3e Food Habits 
Although the Japanese have taken many thousand fur seals along their coaste, they 
have made no accurate investigations of their food habits. Aside from material copied fron 
American reports, no records of actual stomach examinations exiet in the Japanese litera- 
ture. . 
fo justify revising the Fur Seal Convention the Ministry of Agriculture and For- 
eatry etated in 1936 (Appendix C, Item 4) that “not only do they [the fur seals] often 
destroy fishing nets, but they also inflict so much harm to fishermen, snatching fishes 
caught already out of the fishing apparatus; and especially great damage ie felt in the 
fisheries of cuttlefish, herring, sardine, Alaskan pollack, salmon and trout etc." This 
etatement may have been based in part on the unpublished reports of examinations of stom 
ache of 39 fur seals caught between November 1936 and June 1937, supposedly in salmon trout 
nets; these stomache were purchased by the Japanese Government from the fishermen and ex- 
amined at the marine biological laboratories in Hokkaido, Iwate, Miyagi, and Ibaraki pre- 
fectures. At the outset it will be recognized that seals taken in a fish net almost cer~ 
tainly have consumed whatever kind of fish ie trapped in the net. The food identified in 
these stomachs ie listed in Table F according to ite frequency of occurrence. The average 
TABLE F. - STOMACH CONTENTS OF 39 FUR SKALS REPORTED BY JAPANESE 
Number of Stomachs in Percent of 
Kane Which Item Occurred Occurrence 
Trout (salmon trout) 
Squide 
Sardines 
Herring 
Mackerel 
Cod 
Bottom fish 

SOURCE: S3ureau of Fisheries 
38 
