Weddell
Seal Population Dynamics
in
Erebus Bay, Antarctica The
Demographic Consequences of Environmental Variability and Individual
Heterogeneity in Life-history Tactics of a Long-lived Antarctic Marine
Predator
Project
Overview
A breeding population of Weddell seals, a prominent Antarctic apex
predator associated with fast ice, has been intensively
studied in Erebus Bay at the southern extent of the Ross Sea
since 1968. The long-term database, which includes data for
more than 20,586 marked
individuals, contains detailed population information that provides an
excellent opportunity to study linkages between environmental
conditions and demographic processes in the Antarctic. The Erebus Bay
population of Weddell seals in Antarctica's Ross Sea is the most
southerly breeding population of mammal in the world. The
population's location is of special interest as the Ross Sea is one of
the most productive areas of the Southern Ocean, one of the few
pristine marine environments remaining on the planet. The current
project uses analysis and synthesis of long-term data for Weddell seals
with
multi-decadal data on temporal variation in climate, marine, and
sea-ice conditions in the Ross Sea to evaluate a
variety of hypotheses regarding effects of environmental variation on
life-history evolution and population dynamics. Additional details
regarding how
physical drivers influence ecosystem dynamics from the bottom-up are
being obtained by conducting field studies of how seal body mass, a
surrogate for annual variation in marine food resources, varies among
years and individuals. The study’s broad
objective is to evaluate how temporal variation in the marine
environment affects a long-lived mammal’s population
dynamics. The study uses a combination of mark-recapture
analysis of vital rates and population modeling to evaluate
hypotheses regarding how fitness is
affected by temporal environmental
variation and collects longitudinal and cross-sectional data on
body
mass dynamics for mother-pup pairs to evaluate hypotheses
relating environmental variation to changes in body mass and variation
in body mass to effects on population dynamics. Jay Rotella,
Robert Garrott, and Don Siniff are co-PI's on
the study, which is funded by the National
Science Foundation through the U.S.
Antarctic Program. The current
award from the National Science Foundation began August 1, 2012 and
is scheduled to continue through July of 2017.
