9420818 Siniff The Weddell seal is an important upper trophic level species that has been the focus of long-term studies because of its proximity to Antarctic support facilities. The most extensive investigations have involved the Weddell seal population at McMurdo Station where research and monitoring efforts began in the early 1960s and have continued since that date. The objectives of this project are 1) to continue the long-term tagging studies by completing the field work necessary to tag all pups born into the McMurdo sound population and to replace tags on previously tagged individuals so they will not be lost from the tagged population and 2) to update estimates of population parameters annually and to continue the analyses and test of hypotheses associated with this data base. In support of these analyses we will carry out mark-recapture surveys that are necessary to obtain all the estimates required for current capture-recapture models.