Seanet Low Intertidal

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Strongylocentrotus purpuratus (Stimpson, 1857)
Phylum Echinodermata, Class Echinoidea, Subcl. Euechinoidea, Order Echinoida, Family Strongylocentrotidae

Purple sea urchin; test 5 cm diameter (10 cm max), spines short (usually < half diameter of test). Small juveniles often white.

Common in pools, crevices, under rocks; mid- to low intertidal zones & subtidal; exposed & protected outer coast. Herbivorous with a strong preference for giant kelp.

Geo Range: Alaska to Baja
Similar species:
Strongylocentrotus franciscanus is larger, more red, occurs subtidally.

Image: Leptasterias aequalis (upper left); Chlorostoma funebralis (lower rt.)