Presenter: Elizabeth Hasan (University of Alaska Fairbanks)

Description:
Sea otters (Enhydra lutris) are a federally protected species that have been recovering and reoccupying north Pacific coasts since they were nearly extirpated by commercial fur harvesting that ended in 1911. In addition, sea otter populations were adversely impacted by the 1989 Exxon Valdez Oil Spill in the northern Gulf of Alaska. As the sea otter continues to recover from anthropogenic stressors, it is necessary to understand their habitat requirements. This study utilized a novel approach for benthic habitat mapping in relation to sea otters, a VideoRay Mission Pro 5 Romotely Operated Vehicle (ROV), to develop benthic habitat maps in current and potential areas of sea otter occupancy, quantify biological and physical habitat attributes across a gradient of sea otter density, and develop predictive maps for areas of likely sea otter occupation due to expansion. In 2021, ROV video surveys were conducted in nearshore coastal regions of lower Cook Inlet, Alaska: Lake Clark National Park, Kamishak Bay, Eastern Cook Inlet, and Kachemak Bay. ROV data were analyzed for physical and biological habitat composition and sea otter-specific metrics, including number of sea otter pits. Sea otter distribution data previously collected by U.S. Fish and Wildlife Service, U.S. Geological Survey, and the National Park Service were overlaid with habitat maps to create suitability models for sea otter habitat. Some habitat attributes were identified as having greater influence over sea otter presence. Resulting suitability models were applied to mapped habitats with limited sea otter occupancy to predict probability of sea otter occupancy. This study aids resource management around oil and gas fisheries operations by providing comprehensive maps of current and potential sea otter habitats in Cook Inlet. Additionally, this study expands the coastal habitat maps in Alaska and contributes to the growing field of geospatial survey technology.