Project Information
Collaborative Research: The Drivers and Role of Immigration in the Dynamics of the Largest Population of Weddell Seals in Antarctica under Changing Conditions
Short Title:
Drivers and Role of Immigration in Population Dynamics of Weddell Seals in Erebus Bay, Antarctica
Start Date:
End Date:
Reliable predictions are needed for how populations of wild species, especially those at high latitudes, will respond to future environmental conditions. This study will use a strategic extension of the long-term demographic research program that has been conducted annually on the Erebus Bay population of Weddell seals since 1978 to help meet that need. Recent analyses of the study population indicate strong annual variation in reproduction, abundance, and population composition. The number of new immigrant mothers that join the population each year has recently grown such that most new mothers are now immigrants. Despite the growing number of immigrants, the demographic importance and geographic origins of immigrants are unknown. The research will (1) add new information on drivers of annual variation in immigrant numbers, (2) compare and combine information on the vital rates and demographic role of immigrant females and their offspring with that of locally born females, and (3) add genomic analyses that will quantify levels of genetic variation in and gene flow among the study population and other populations in the Ross Sea. The project will continue the long-term monitoring of the population at Erebus Bay and characterize population dynamics and the role of immigration using a combination of mark-recapture analyses, stochastic population modeling, and genomic analyses. The study will continue to (1) provide detailed data on individual seals to other science teams, (2) educate and mentor individuals in the next generation of ecologists, (3) introduce two early-career, female scientists to Antarctic research, and (4) add genomics approaches to the long-term population study of Erebus Bay Weddell seals. The Informal Science Education program will expand on the project’s recent and successful efforts by producing and delivering short-form videos through an interactive web portal and diverse social-media technologies. The Informal Science Education program will continue to update and add new topics to a multimedia-enhanced electronic book about the project’s research on Weddell seals that will be freely available to the public. The outreach efforts will increase the length of the book from ~140 to ~225 pages and add new topics such as learning about seals using genomics and how seals respond to a changing world.
Person Role
Rotella, Jay Investigator and contact
Chen, Nancy Co-Investigator
Antarctic Organisms and Ecosystems Award # 2147554
Antarctic Organisms and Ecosystems Award # 2147553
Antarctic Organisms and Ecosystems Award # 1640481
The Consequences of Maternal effects and Environmental Conditions on Offspring Success in an Antarctic Predator

The consequences of variation in maternal effects on the ability of offspring to survive, reproduce, and contribute to future generations has rarely been evaluated in polar marine mammals. This is due to the challenges of having adequate data on the survival and reproductive outcomes for numerous offspring born in diverse environmental conditions to mothers with known and diverse sets of traits. This research project will evaluate the survival and reproductive consequences of early-life environmental conditions and variation in offspring traits that are related to maternal attributes (e.g. birth date, birth mass, weaning mass, and swimming behavior) in a population of individually marked Weddell seals in the Ross Sea. Results will allow an evaluation of the importance of different types of individuals to the Weddell Seal's population sustenance and better assessments of factors contributing to the population dynamics in the past and into the future. The project allows for documentation of specific individual seal's unique histories and provisioning of such information to the broader science community that seeks to study these seals, educating graduate and undergraduate ecology students, producing science-outreach videos, and developing a multi-media iBook regarding the project's science activities, goals and outcomes.

The research has the broad objective of evaluating the importance of diverse sources of variation in pup characteristics to survival and reproduction. The study will (1) record birth dates, body mass metrics, and time spent in the water for multiple cohorts of pups (born to known-age mothers) in years with different environmental conditions; (2) mark all pups born in the greater Erebus Bay study area and conduct repeated surveys to monitor fates of these pups through the age of first reproduction; and (3) use analyses specifically designed for data on animals that are individually marked and resighted each year to evaluate hypotheses about how variation in birth dates, pup mass, time spent in the water by pups, and environmental conditions relate to variation in early-life survival and recruitment for those pups. The research will also allow the documentation of the population status that will contribute to the unique long-term database for the local population that dates back to 1978.

AMD - DIF Record(s)
Deployment Type
Jay Rotella field camp
Data Management Plan
Product Level:
0 (raw data)
  1. Brusa, J. L., Rotella, J. J., Garrott, R. A., Paterson, J. T., & Link, W. A. (2019). Variation of annual apparent survival and detection rates with age, year and individual identity in male Weddell seals (Leptonychotes weddellii) from long‐term mark‐recapture data. Population Ecology, 62(1), 134–150. (doi:10.1002/1438-390x.12036)
  2. Paterson, J. T., Rotella, J. J., Link, W. A., & Garrott, R. (2018). Variation in the vital rates of an Antarctic marine predator: the role of individual heterogeneity. Ecology, 99(10), 2385–2396. (doi:10.1002/ecy.2481)
  3. Rotella, J. J. (2022). Patterns, sources, and consequences of variation in age‐specific vital rates: Insights from a long‐term study of Weddell seals. Journal of Animal Ecology. Portico. (doi:10.1111/1365-2656.13870)
  4. Powell, J., Kalinowski, S., Taper, M., Rotella, J., Davis, C., & Garrott, R. (2023). Evidence of an Absence of Inbreeding Depression in a Wild Population of Weddell Seals (Leptonychotes weddellii). Entropy, 25(3), 403. (doi:10.3390/e25030403)
  5. Foster-Dyer, R. T. N., Goetz, K. T., Pinkerton, M. H., Iwata, T., Holser, R. R., Michael, S. A., Pritchard, C., Childerhouse, S., Rotella, J., Federwisch, L., Costa, D. P., & LaRue, M. A. (2023). First observations of Weddell seals foraging in sponges in Erebus Bay, Antarctica. Polar Biology, 46(7), 611–621. (doi:10.1007/s00300-023-03149-1)
  6. Anderson, A. K., Levinson, P. M., Conklin, A., & Rotella, J. J. (2024). Observations of Weddell seal (Leptonychotes weddellii) supernumerary nipples. Polar Biology. (doi:10.1007/s00300-024-03228-x)

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