Ecology of Marine Mammals
-- Ecology of Marine Mammals --
Upper Trophic Level Research: Polar Bears and Ringed Seals
Malcolm Ramsay and Sean Farley
Nearshore Arctic waters are home to more than a dozen species of mammals
from three orders (Cetacea, Carnivora and Pinnipedia). Prior to the AOS-94
transect, our knowledge of these mammals found in Arctic waters off the con-
tinental shelf consisted primarily of anecdotal accounts from explorers' jour-
nals and ships' logs. Logistical constraints have limited opportunities for biolo-
gists to work in the offshore pack ice, so there were few hard data, even on
simple presence or absence, for species outside of a narrow band (about 200
km) from shore accessible by shore-based aircraft. The AOS-94 transect offered
the first dedicated opportunity to monitor polar bears and observe other mar-
ine mammals in the permanent pack ice environment of the Arctic Ocean.
Although closely related to the terrestrial brown and black bears of North
America and Asia, polar bears have adopted a marine-associated life style and
are intimately associated with the sea ice of the Arctic Basin. Their southern
range approximates, to a very high degree, the maximum extent of that ice in
winter. They roam over the sea ice in search of their prey, primarily ringed
seals, but bearded and ribbon seals as well. As carnivores, polar bears are at the
top of the relatively long Arctic marine food chain and, accordingly, are no-
where abundant. Furthermore, individual bears move over very large areas
each year in search of their prey.
All polar bears studied to date have been found to be members of relatively
discrete, coastal subpopulations. The northern boundaries for those subpopula-
tions on the periphery of the Arctic Ocean are poorly known. Prior to AOS-
94, marine mammal researchers assumed that the central Arctic Basin was a
biological desert that could not support a significant biomass of upper trophic
level vertebrates. We viewed participation in the AOS-94 as a pilot project to
determine whether it is feasible for vertebrate ecologists to work productively
in heavy pack ice and whether polar bears and other marine mammals could
be located there.
If bears were found, we wanted to determine what their affinities were with
known coastal-associated populations and how the movement patterns of in-
Malcolm Ramsay is from the Department of Biology at the University of Saskatchewan in Saskatoon, Saskatchewan,
Canada. Sean Farley is from the Department of Zoology at Washington State University in Pullman, Washing-
ton, U.S.A.
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