Fred Bavendam / Purple Sea Urchin (Strongylocentrotus purpuratus) and Red Sea Urchin (Strongylocentrotus franciscanus) group, Channel Islands, California

Fred Bavendam / Green Sea Urchin (Strongylocentrotus droebachiensis) group and one Red Sea Urchin (Strongylocentrotus franciscanus), Quadra Island, British Columbia, Canada

Flip Nicklin / Purple Sea Urchin (Strongylocentrotus purpuratus) with tube feet extended into water to feed, California

Pascal Kobeh / Reef covered with two red Stomphia sea anemones (Stomphia coccinea), with Plumose anemones (Metridium senile), Red soft corals (Eunephthya / Gersemia rubiformis) and Green sea urchins (Strongylocentro...

Pascal Kobeh / Atlantic / Common rock crab (Cancer irroratus) on the reef in the middle of green sea urchins (Strongylocentrotus droebachiensis) Gulf of Saint Lawrence, Canada

SCOTLAND: The Big Picture / Horse mussel bed (Modiolus modiolus) with Brittle stars (Ophiothrix fragilis),Edible crab (Cancer pagurus) and Northern sea urchin (Strongylocentrotus droebachiensis) Sheltand Islands, Scotland, UK, S...

Olga Kamenskaya / Purple sea urchin (Strongylocentrotus purpuratus) off the coast of Svalbard, Norway. September.

Richard Herrmann / Red Sea Urchin (Strongylocentrotus franciscanus) and Purple Sea Urchin (Strongylocentrotus purpuratus) feeding on Southern Sea Palm (Eisenia arborea) creating urchin barren, Santa Cruz Island, Channel...

Franco Banfi / Purple sea urchin (Strongylocentrotus purpuratus) Little Strytan dive site, Eyjafjordur nearby to Akureyri, northern Iceland, North Atlantic Ocean.

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus) group feeding on Giant Kelp (Macrocystis pyrifera), creating urchin barren, California

Norbert Wu / Brittle Star (Ophiothrix spiculata) group and Purple Sea Urchins (Strongylocentrotus purpuratus), California

Pascal Kobeh / Colony of Red sea urchins (Strongylocentrotus franciscanus) at the feet of Bull kelps (Nereocystis luetkeana) Vancouver Island, British Columbia, Canada. Pacific Ocean.