There is currently some question as to whether the biological resources of the Antarctic marine ecosystem are divided into stocks that can be managed separately or constitute a single community which is influenced by common events over a large geographic area. In order to address this question, comparable data for populations of the same species collected from different regions over a large time span are needed. Researchers have been monitoring reproductive rates of Weddell seals at several locations in Antarctica, but none has yet attempted to compare the various data sets. Testa proposes to analyze and compare existing data on the annual reproductive rates of Weddell seals from McMurdo Station (U.S.) with those from Davis (Australia) and Signy Island (British) Stations to determine whether large-scale factors influence reproductive success in distinct populations from widely separated geographic locations. The work will be conducted in collaboration with members of the British Antarctic Survey and the Australian National Antarctic Research Expedition. Data also exists on food habits of Weddell seals at these locations, and will be utilized for interpretation of data sets. Results will provide a foundation for better management of Antarctic marine biological resources, as well as an opportunity for international collaboration and dissemination of information. Results should also further our understanding of life-history evolution and population ecology of large mammals.