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Contact Us
Bob Garrott & Jay Rotella
Department of Ecology
308 Lewis Hall
Montana State University
Bozeman, MT 59717-3460

Tel: (406) 994-4548
Fax: (406) 994-3190

> Department of Ecology
Weddell Seal Population Dynamics
in
Erebus Bay, Antarctica

Interactions of Environmental Variability, Life History Traits,
and Demography in an Apex Antarctic Predator

reading tags

Project Description

The Ross Sea, a geographically well-defined embayment of the Antarctic continental shelf,
provides an outstanding scientific opportunity in the Southern Ocean for gaining insights into marine ecosystem processes due to its unique combination of attributes.  Of note, the Ross Sea provides a valuable opportunity for a contrasting study of the ecological consequences of global climate change: while most regions of the globe are experiencing warming trends, the Ross Sea is experiencing a general cooling of air temperatures and a consequent lengthening of the sea-ice season.  An intensive study of a breeding population of Weddell seals in the Erebus Bay region of eastern McMurdo Sound at the southern extent of the Ross Sea was initiated in 1968 and represents one of the longest continuous field investigations of a long-lived mammal in existence.

Over the 38-years of this study, a total of 17,360 animals have been tagged, and 168,568 re-sightings have been logged in the database. Emphasis has consistently been on maintaining
and enhancing annual demographic data through the use of mark-recapture techniques.  Because all pups born within the study area have been tagged since 1973 and because this species
demonstrates strong philopatric behavior, ~80% of the seals are marked and >65% of the individuals in the population are currently both marked and of known age.

This study and the database accrued through nearly four decades of intensive effort provide a
strong foundation and unique opportunity to extend our ecological knowledge of population and
ecosystem processes. Inferences from this multi-decadal study extend beyond the Ross Sea and contribute to a broader body of knowledge about the evolution of life-history strategies and population dynamics of long-lived organisms in variable environments. Such information is vital to understanding and conserving many other animal populations. In our current work we continue to build on this foundation with two lines of investigation that combine (1) mark-resight and other advanced analytical tools to describe and understand population processes and (2) studies of seal mass dynamics to link demographic variability with ecosystem processes.

To meet the objective of our current research agenda and to test the hypotheses of primary interest, we use a variety of approaches and methodologies that can be categorized into three general initiatives: 1) continuation of annual seal tagging and mark-recapture surveys to maintain continuity of the long-term demographic database, 2) comprehensive analyses and integration of the long-term demographic database using recently developed analytical approaches, and 3) collection and analyses of individual body mass dynamics and the development of multiple regression models to evaluate the hypotheses posed.

Data on animals tagged are available here.  The data can be used to obtain information on:
  1. Individual tag information including the most recent tag numbers and colors,
  2. Year when each animal was tagged,
  3. Animal sex,
  4. Animal age when tagged (for animals tagged as pups, age can be calculated), and
  5. Date the animal was last observed.
If you have questions about the project or seal database, please contact Bob Garrott or Jay Rotella by e-mail, surface mail, or phone.


Polar-Palooza Podcast from the Ice

POLAR-PALOOZA is a multimedia initiative - supported by both NSF and NASA - involving researchers, Alaskan natives, in-person presentations at science centers and natural history museums, video and audio podcasts, and more.  In 2007, a film crew visited our project and produced a podcast with excellent footage of the seals and the area in which they live.


Field camp for seal studies

View Text-only Version Text-only Updated: 06/03/2008
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