Walruses in Svalbard numbered in the hundreds of thousands before 3 centuries of over-harvesting brought the population to the verge of extinction. Today this stock is in an early phase of recovery; it consists of a few thousand animals. Little is known a bout habitat utilization, foraging areas or behaviour in this population. This program will use satellite telemetry to identify important feeding areas for walruses. Geographical position data in combination with detailed dive information will provide nov el insight into habitat use by this large pinniped. Scat analyses, isotope analyses and surveys of potential benthic prey will provide more specific information about diet. Haul-out behaviour studies, in addition to the satellite data activity budgets wi ll permit the calculation of correction factors for aerial surveys. In addition, we will study the exposure to and effects of pollutants and conduct a general health assessment based on clinical serum chemistry parameters. We will also study the potential of the contaminant mixtures in the diet of walruses to cause endocrine disruptions. Finally, based on information on haul-out behaviour from the satellite telemetry project and observational data, we will conduct a photographic ae rial survey to produce a current, accurate population estimate.