MARINE MAMMAL COMMISSION — Annual Report for 1992 
entangled and died at sea where mortality is unlikely 
to be observed and is more likely to occur. Some 
entanglement studies in the late 1980s suggested that 
fur seal pups readily interact with and become entan- 
gled in debris, and that entanglement-related mortality 
could have been greater than 14 percent in the late 
1970s and early 1980s. 
A third factor may be incidental take in large-scale 
driftnet fisheries that began operating on the high seas 
of the North Pacific Ocean in 1978 and expanded 
rapidly thereafter. Data on the number of fur seals 
taken in high seas driftnet fisheries prior to 1990 are 
almost nonexistent. Monitoring programs since 1989 
have provided some useful data; however, they have 
not yet been analyzed fully with regard to potential 
fur seal incidental take levels. As discussed in Chap- 
ter IV, a global moratorium on high seas driftnet 
fisheries took effect after 31 December 1992. This 
should largely eliminate the effect of high seas driftnet 
fisheries on fur seals. However, driftnet fishing may 
continue or intensify in Russia’s Exclusive Economic 
Zone. 
A fourth factor in the decline may be the reduction 
of food resources for fur seals in the North Pacific. 
Although data for related factors such as body size 
and growth indicate otherwise, a decrease in fur seal 
prey species due either to over-fishing or natural 
factors, such as climate change, cannot be ruled out. 
It is conceivable that a depletion in food supplies in an 
area of particular importance to one or more age and 
sex classes of fur seals may be a significant factor. 
Other factors that may have influenced population 
trends over the past four decades include toxic con- 
taminants, disease, and predation. There are few data 
to suggest that these have been significant. 
Subsistence Harvest 
Northern fur seals were harvested commercially for 
their pelts from the 1700s until 1984. On the Pribilof 
Islands, they are now taken only for consumption by 
Aleut residents. As noted in previous annual reports, 
the nations involved in commercially harvesting fur 
seals managed seal herds under a series of internation- 
al agreements during most of the 20th century. 
Between 1957 and 1984 northern fur seals were man- 
42 
aged cooperatively by the Governments of Canada, 
Japan, the Soviet Union, and the United States under 
provisions of the Interim Convention on Conservation 
of North Pacific Fur Seals. The interim convention 
sought to maintain fur seals at a population level that 
would provide the greatest annual harvest, with due 
regard for the productivity of other living marine 
resources. The convention lapsed in 1984 when the 
United States Senate declined to ratify a protocol to 
extend it. As a result, management authority in the 
United States became subject to domestic laws, 
including the Fur Seal Act of 1966 (16 U.S.C. § 1151 
et seq.) and the Marine Mammal Protection Act. 
Under the latter Act, commercial harvesting of fur 
seals is prohibited and subsistence harvesting has been 
limited to the Aleut residents of the Pribilof Islands. 
The subsistence harvest is regulated by the Nation- 
al Marine Fisheries Service under the Fur Seal Act 
and the Marine Mammal Protection Act. The regula- 
tions developed under these laws require that, before 
each year’s harvest, the Service estimate the number 
of seals needed for subsistence purposes by Native 
residents of the Pribilof Islands. To develop this 
estimate, the Service considers the previous year’s 
harvest levels, economic conditions in the Aleut 
communities, and the size of the Aleut population. 
Once the estimated minimum number of seals for a 
given harvest is taken, the harvest is suspended until 
the Service determines whether subsistence needs have 
been met or whether an additional take of seals is re- 
quired. Subsistence harvest levels from 1985 through 
1992 are shown in Table 5. 
In the 28 May 1992 Federal Register the Service 
solicited comments on proposed estimated take levels 
for the 1992 Pribilof Islands fur seal subsistence 
harvest. The Service estimated that Native subsis- 
tence needs in 1992 would be met by a take of be- 
tween 1,645 and 2,000 seals on St. Paul Island and 
between 281 and 500 seals on St. George Island. On 
3 August 1992, the Service published final estimates 
for the subsistence fur seal harvest in the Federal 
Register. The final estimates were unchanged from 
proposed estimates of 28 May. As noted in Table 5, 
the 1992 subsistence harvest totals were 1,482 seals 
on St. Paul Island and 194 seals on St. George Island. 
