Inter-Research > ESR > Prepress Abstract

ESR prepress abstract   -  DOI:

Informing sea otter reintroduction through habitat and human interaction assessment

Dominique V. Kone*, M. Tim Tinker, Leigh G. Torres

*Corresponding author:

ABSTRACT: Sea otters Enhydra lutris have been absent from Oregon, USA, following their extirpation over a century ago. Stakeholder groups and native tribes are advocating for sea otter reintroduction to restore historic populations in Oregon. We investigated the potential for successful sea otter reintroduction by: (1) assessing sea otter habitat in Oregon, by estimating expected equilibrium sea otter densities as a function of habitat variables; and (2) spatially relating areas of high expected sea otter densities to human activities (e.g. fisheries, recreation, vessel activity, protected areas) to anticipate potential disturbance or fishery resource competition. We estimated 4538 (1742 – 8976; 95% CI) sea otters could exist in Oregon, with higher expected abundance (N = 1551) and densities (= 2.45 otters km-2) within the southern region. Most core habitat areas (97%), representing clusters of high expected sea otter densities, overlapped with some form of human activity. While commercial shipping and tow lanes overlapped little (1%) with core habitat areas, recreational activities (58%) and fisheries (76%) had a higher degree of overlap, posing higher disturbance risk to sea otters. We anticipate higher resource competition potential between sea otters and the commercial red sea urchin fishery (67% of harvest areas) than the commercial Dungeness crab fishery (9% of high-catch crabbing grounds). Our study presents the first published carrying capacity estimate for sea otters in Oregon and can provide sea otter population recovery targets, focus attention on ecological and socioeconomic considerations, and help to inform a recovery plan for a resident sea otter population in Oregon. Our findings suggest current available habitat may be sufficient to support a sea otter population in Oregon, but resource managers may need to further investigate and consider whether current human activities might conflict with sea otter reestablishment in Oregon, if plans for a reintroduction continue.