Between the Purple Sea Urchin (Strongylocentrotus purpuratus) and Giant Sea Star (Pisaster giganteus) on this busy patch of reef lies a Hilton’s Aeolid (Phidiana hiltoni) nudibranch. Carmel Pinnacles State Marine Reserve, Carmel-by-the-Sea, California.
A red sea urchin coinhabits a bustling Monterey Peninsula reef with purple sea urchins that have stripped the area of most of its kelp.
