Decadal Bering Sea seascape change: Consequences for Pacifi c walruses and indigenous hunters

The most signifi cant factors currently affecting the Pacifi c walrus (Odobenus rosmarus divergens) population are climate change and consequent changes in sea-ice morphology and dynamics. This paper integrates recent physical sea-ice change in the Bering Sea with biological and ecological conditions of walruses in their winter-spring reproductive habitat. Historically, walrus in winter-spring depended on a critical mass of sea-ice habitat to optimize social networking, reproductive fi tness, feeding behavior, migration, and energetic effi ciency. During 2003-2013, our cross-disciplinary, multiscale analysis from shipboard observations, satellite imagery, and ice-fl oe tracking, reinforced by information from indigenous subsistence hunters, documented change of sea-ice structure from a plastic continuum to a "mixing bowl" of ice fl oes moving more independently. This fragmentation of winter habitat preconditions the walrus population toward dispersal mortality and will also negatively affect the availability of resources for indigenous communities. We urge an expanded research and management agenda that integrates walrus natural history and habitat more completely with changing sea-ice morphology and dynamics at multiple scales, while also meeting the needs of local communities.