Monday, Apr 27, 2020
Alex Wilbanks

    A Pacific purple sea urchin nestling in between coral and rocks at Fitzgerald Marine Reserve.

    As a Natural Resource Management Intern I visit many of the parks to analyze different habitats and support vegetation management activities. During my first visit to Fitzgerald Marine Reserve myself and two colleagues took the opportunity to acquaint ourselves with the tidepools. While walking along the rocks we noticed a bright purple sea urchin that stood out in comparison to the others. Using a wildlife identification app, we were able to determine it was the pacific purple sea urchin (Strongylocentrotus purpuratus). 

    The Pacific purple sea urchin can be found on rocky shorelines along the western coast of the United States. Although endemic to the region pacific purple sea urchin populations have risen significantly with the loss of sunflower sea stars (Pycnopodia helianthoides), a primary predator of Pacific purple sea urchins. Other primary predators of Pacific purple sea urchins include sea otters and sheepshead fish. Unchecked Pacific purple sea urchin populations have become problematic as they have contributed significantly to the loss of kelp forests along the western coast of the United States. 

    One interesting behavior performed by Pacific purple sea urchins is they cover themselves with shells, rocks, and pieces of algae. Scientists believe that this is done to protect against drying out and predation from gulls. 

    Learn more about San Mateo County Parks Natural Resource Management »