Monitoring population status of sea otters (Enhydra lutris) in Glacier Bay National Park and Preserve, Alaska: options and considerations

Sea otters (Enhydra lutris) are recolonizing Glacier Bay, Alaska, after decades of absence, playing a pivotal role in structuring nearshore ecosystems. This study evaluates monitoring options to assess their population status and understand their ecological impacts, including changes in kelp abundance and consumer dynamics. The primary method proposed is aerial surveys, with analyses to detect interannual trends and reduce variation in abundance estimates. Alternate techniques include quantifying otter diets and energy intake rates, as well as detecting changes in ages at death. The study also identifies directed research needs to deepen the understanding of sea otter population dynamics and their effects on the Glacier Bay ecosystem, providing a framework for interpreting monitoring results.

Esslinger, G. G., Esler, D. N., Howlin, S., & Starcevich, L. A. (2015). Monitoring population status of sea otters (Enhydra lutris) in Glacier Bay National Park and Preserve, Alaska: options and considerations. Open-File Report. https://doi.org/10.3133/ofr20151119