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Purple Sea Urchin - Strongylocentrotus purpuratus
Photo by Kathy DeWet-Oleson

The purple sea urchin is a common inhabitant of rocky reef areas both in the low tide zone and shallow subtidal zone. This medium sized species ranges in size from 5-10 cm (2-4 in) and is lavender or light shade of purple. This species reaches reproductive maturity by age two, when it is only about 1 inch in size. In areas where sea urchin predation is low, purple urchins are known for dramatically altering the kelp forest ecosystem and leaving behind what is known as an urchin barren.

Purple Sea Urchin
(Strongylocentrotus purpuratus)

Alaska to Baja California

Rocky reefs, low intertidal to shallow subtidal



The status of this species is representative of the populations within the waters of this Sanctuary only, not global populations.

Quick Fact
The purple urchin is often entombed in a hollow rocky area that is formed by the spines and grinding teeth of the animal.

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- Stanford University