Global climate change is expected to have myriad impacts on marine mammals, from changes in prey availability to habitat loss. For land-dependent marine mammals such as seals and sea lions, sea level rise (SLR) and other coastal hazards could result in the loss of habitat required for reproduction and rest. As current haul-out sites disappear, these animals will look for new places to rest and breed, which will increasingly put them in conflict with human activities. The identification of areas in central California that could be critically threatened by coastal climate change, and potential adaptation options remain uncharacterized.

SLR, when combined with storms and tides, can rapidly change shoreline morphology, compromising vital terrestrial habitat for semi-aquatic marine organisms, including pinnipeds. The widespread coastal flooding and erosion experienced by central California during the winter of 2023 further highlights the importance and urgency of this issue. The effects of the atmospheric rivers on local pinniped populations are yet to be fully determined, however, there were observable changes to the distributions of elephant seals hauled out to breed at Año Nuevo State Park and Point Reyes National Seashore at the time these storms hit.

This project has the main objective to identify which haul-out sites in central California are most likely to be impacted by SLR and coastal climate change. We plan to:

1. Use data from the USGS Coastal Storm Modelling System, satellite imagery, and drone surveys of seal and sea lion populations in the region to characterize when and where pinnipeds could be affected by extreme coastal flooding and lose terrestrial habitat that is critical for reproduction.

2. Work with reserve managers (UC Natural Reserve System and California State Parks) to anticipate these changes and to proactively identify solutions, including