Chapter III — Species of Special Concern 
ee 
To obtain and evaluate the most up-to-date infor- 
mation available, the Commission contracted in 1991 
for an update of the 1988 harbor seal species account. 
At the end of 1992, the report was undergoing final 
review; it is expected to be published in 1993. 
With respect to the National Marine Fisheries 
Service’s efforts to develop a conservation plan to 
assess and describe what should be done to stop and 
reverse the harbor seal decline in Alaska, the Com- 
mission wrote to the Service on 29 September 1992 
urging it to conclude a contract with the University of 
Alaska to develop a draft harbor seal conservation 
plan. By letter of 5 October 1992, the Service 
advised the Commission that (1) all existing data 
indicate a significant decline in harbor seal numbers 
throughout the Gulf of Alaska; (2) a conservation plan 
for harbor seals in the region is necessary; (3) it had 
contracted with the University of Alaska to develop 
the conservation plan; and (4) it would appoint a 
harbor seal review team, to include personnel from 
the Alaska Department of Fish and Game and the 
Service’s National Marine Mammal Laboratory and 
Office of Protected Resources. The Service further 
noted that it had developed a draft harbor seal status 
review that it will use, along with the Commission’s 
1988 harbor seal species account, as background for 
the conservation plan, and that it hoped to have a 
draft plan completed by the end of 1992. At the end 
of 1992 the Service had not completed the conserva- 
tion plan. The Commission’s updated species account 
with research and management recommendations will 
be made available to the Service early in 1993. 
Northern Fur Seal 
(Callorhinus ursinus) 
Northern or North Pacific fur seals occur seasonal- 
ly in waters along the North Pacific rim from Califor- 
nia to Japan. Some animals also use pelagic waters of 
the North Pacific Ocean, presumably for feeding. 
Major breeding locations occur on Robben Island and 
the Kuril Islands in the Okhotsk Sea, in the western 
Bering Sea on the Commander Islands, and on the 
Pribilof Islands in the eastern Bering Sea. The 
species’ largest breeding colonies are on St. Paul and 
St. George Islands in the Pribilof Islands and repre- 
41 
sent about three-fourths of the total number of north- 
ern fur seals worldwide. 
The Pribilof Islands fur seal population is estimated 
to have numbered 2 to 2.5 million animals as recently 
as the early 1950s. This number is thought to equal 
the population size before exploitation began in the 
mid-1700s. Over the past four decades, however, the 
population has declined significantly. From the late 
1950s to the mid-1980s, the number of fur seals on 
the Pribilof Islands experienced a net reduction 
exceeding 50 percent. An even greater decline was 
observed at Robben Island. Population estimates from 
1983 placed the number of seals on the Pribilof 
Islands at about 877,000 animals. In 1988 the popula- 
tion was designated as depleted under the Marine 
Mammal Protection Act. Data from 1990 indicate 
that the population has increased since then to slightly 
more than 1,000,000 animals. This appears to be due 
primarily to an increase in the number of male fur 
seals resulting from the cessation of the commercial 
fur seal harvest in 1984 (see below for discussion of 
the fur seal harvest). 
Causes of the observed declines since the late 
1950s are only partly known. As discussed in past 
annual reports, several factors may be contributing to 
the decline and subsequent weak recovery of northern 
fur seals. For instance, a harvest of more than 
300,000 female fur seals between 1956 and 1968 
reduced the number of breeding adults and nursing 
females. This is believed to have been the major 
cause of declines through the early 1970s. It does 
not, however, explain the continuing decline observed 
during the early 1980s. 
A second factor may be entanglement of fur seals 
in marine debris, particularly net fragments and 
packing bands. The data on the scope and effect of 
entanglement on fur seals are equivocal. Observed 
annual declines in the Pribilof Islands of 4-8 percent 
between the mid-1970s and the early 1980s appeared 
to be largely due to juvenile mortality during the first 
years of life at sea. Although initially attributed 
largely to entanglement, direct evidence to support 
this conclusion was weak. Observed entanglement 
rates of juveniles on land in the 1970s and 1980s were 
generally at or below 0.4 percent. This does not, 
however, take into account fur seals that became 
