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

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...

Nick Upton / Green sea urchin (Psammechinus miliaris) in a rockpool, Cornwall, England, UK, September.

Solvin Zankl / Naked green sea urchin (Arbacia dufresnii) Comau Fjord, Patagonia, Chile.

Solvin Zankl / Naked green sea urchin (Arbacia dufresnii) Comau Fjord, Patagonia, Chile

Solvin Zankl / Naked green sea urchin (Arbacia dufresnii) Comau Fjord, Patagonia, Chile, Atlantic Ocean

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...

Alex Mustard / A view through Kelp forest (Laminaria hyperborea) with Common sea urchins (Echinus esculentus) grazing on the algae, Farne Islands, Northumberland, UK, North Sea, August

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

Scott Leslie / Winter Flounder (Pleuronectes americanus) camouflaged among Green Sea Urchins (Strongylocentrotus droebachiensis) barren, Passamaquoddy Bay, Maine