Archaeological faunal assemblages are time-stamped biological records that allow us to test long-standing assumptions about species’ ecological roles and anchor modern management goals to pre-industrial baselines. By pairing zooarchaeological data with isotopic analyses, we can reconstruct historical diets, trophic positions, and habitat use. In this talk, Emma illustrates this approach with the sea otter (Enhydra lutris), a keystone marine predator nearly driven extinct by the Euro-American maritime fur trade. She presents isotopic data from sea otter bones recovered at archaeological sites in southeast Alaska, northern Oregon, and California; this archaeological record reflects the deep and enduring ecological stewardship by Indigenous communities of the Pacific coast. These localities also span a gradient of modern sea otter population recovery trajectories, including regions (Oregon) where sea otters existed historically but have not yet successfully recolonized. Prior to the fur trade, sea otters occupied broad ecological niches in all regions. In southeast Alaska, isotopic data suggest that recovering sea otter populations may overlap strongly with resources targeted by traditional and subsistence fisheries, foreshadowing potential conflicts. In Oregon, kelp forests stand out as critical habitat for past sea otter populations and should be considered in future reintroduction efforts. In California, modern sea otters display markedly contracted diet breadth relative to their pre-fur-trade predecessors, exposing lost trophic roles invisible to modern monitoring. By supplying ecological insights otherwise unavailable, this study pinpoints key habitats and trophic links essential for recovery of a keystone species, illustrating the value of zooarchaeology and isotopic analysis in linking historical ecology with contemporary conservation efforts.