Donald B. Siniff OPP-9725820 Abstract The Weddell seal is found in regions of pack ice or fast ice close to the Antarctic continent. This species has been the focus for long-term population studies in McMurdo Sound since the mid-1960's. This data set, one of the few of its kind in the world, has provided valuable knowledge towards an understanding of the survival and reproductive patterns of a long-lived vertebrate. Within the framework of this study, an examination of the breeding system and reproductive fitness will be conducted, using recently developed techniques in molecular biology. An examination of the behavioral ecology and mating system through paternity analysis of breeding males will provide precise estimates of reproductive success and effective population size in this aquatic breeding species. A second aspect of the study will focus on population demographics, which is a continuation of the annual analyses, parameter estimation and hypothesis testing associating with the existing 30-year data base. A new addition to this aspect is a comprehensive analysis of the population dynamics focusing on the role that immigration and emigration play in the population dynamics. As the southern-most breeding mammal in the world, the Weddell seal exemplifies an extreme in environmental adaptability. Knowledge of the strategies employed in this environment will contribute to the basic understanding of pinniped evolution and population dynamics and competition in marine mammals.
