Jeff Rotman / Wolf eel (Anarrichthys ocellatus) eating Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean.

Jeff Rotman / Wolf eel (Anarrichthys ocellatus) eating Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean.

Floris van Breugel / Giant Red Sea Urchins (Strongylocentrotus franciscanus) Purple sea urchins (Strongylocentrotus purpuratus) and Sea Anenomes (Anthopleura) underwater, in tide pools along Californian coastline, USA.

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

Georgette Douwma / Purple sea urchins, California USA

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.

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

Scott Leslie / Northern Red Sea Anemone (Tealia felina) among Green Sea Urchins (Strongylocentrotus droebachiensis), Passamaquoddy Bay, Maine

Scott Leslie / Green Sea Urchin (Strongylocentrotus droebachiensis) barren with Orange-footed Sea Cucumber (Cucumaria frondosa), Passamaquoddy Bay, Maine

Scott Leslie / Common Shore Crab (Carcinus maenas) camouflaged amongst Green Sea Urchins (Strongylocentrotus droebachiensis) barren, Passamaquoddy Bay, Maine

Scott Leslie / Green Sea Urchin (Strongylocentrotus droebachiensis) barren, Passamaquoddy Bay, Maine

Franco Banfi / Giant red sea urchin (Strongylocentrotus franciscanus) Vancouver Island, British Columbia, Canada, Pacific Ocean

Pascal Kobeh / Underwater reef covered with a colony of Red sea urchins (Strongylocentrotus franciscanus), Alaska, USA, Gulf of Alaska. Pacific ocean.

Jeff Rotman / Close-up of Metridium Anemones (Metridium farcimen) and Red Sea Urchins (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean

Jeff Rotman / Spines of Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean

Jeff Rotman / Spines of Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean

Jeff Rotman / Wolf eel (Anarrichthys ocellatus) eating Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean.

Jeff Rotman / Wolf eel (Anarrichthys ocellatus) eating Red Sea Urchin (Strongylocentrotus franciscanus). Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean.

MYN / Jerry Monkman / Green sea urchin (Strongylocentrotus droebachiensiss) Rye, New Hampshire, USA, August. meetyourneighbours.net project

MYN / Jerry Monkman / Green sea urchin (Strongylocentrotus droebachiensiss) Rye, New Hampshire, USA, August. meetyourneighbours.net project

Norbert Wu / Red Sea Urchin (Strongylocentrotus franciscanus) and brittlestars, Campbell River, Vancouver Island, British Columbia, Canada

Jeff Rotman / Green sea urchins (Stronglyocentrotus droebachiensiss) scavenging and grazing, USA, North Atlantic Ocean.

Fred Bavendam / Sea Star (Mediaster aequalis), California Sea Cucumber (Parastichopus californicus) and Red Sea Urchin (Strongylocentrotus franciscanus), British Columbia, Canada

Fred Bavendam / Red Sea Urchin (Strongylocentrotus franciscanus) in urchin barren, Vancouver Island, British Columbia, Canada

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus), Vancouver Island, British Columbia, Canada

Norbert Wu / Sunflower Sea Star (Pycnopodia helianthoides) and Purple Sea Urchin (Strongylocentrotus purpuratus) in feeding on Frilled Sea Anemones (Metridium senile), Vancouver Island, British Columbia, Canada

Scott Leslie / Green Sea Urchin (Strongylocentrotus droebachiensis) barren, caused by urchins eating all the kelp, Nova Scotia, Canada

Scott Leslie / Green Sea Urchin (Strongylocentrotus droebachiensis) barren, having eaten all the kelp with Shorthorn Sculpin (Myoxocephalus scorpius), Nova Scotia, Canada

Jeff Rotman / Purple Sea Urchins (Strongylocentratus purpuratus) colony feeding on kelp bases. Channel Islands, USA, Pacific Ocean.

Konstantin Mikhailov / Sea-urchins (Strongylocentrotus pulchellus) and Starfish, Sea of Japan, Peter Great Gulf, SE Russia

Doug Perrine / Spiny / Piked dogfish {Squalus acanthias} with Red sea urchins {Strongylocentrotus franciscanus} Quadra Island off Vancouver Island, Discovery Passage, British Columbia, Canada. Note - also known as...

Peter Scoones / Green sea urchins (Strongylocentrotus droebachiensiss) Galapagos islands

Doug Perrine / Spiny / Piked dogfish {Squalus acanthias} with Red sea urchins {Strongylocentrotus franciscanus} and orange sea pen {Ptilosarcus gurneyi} Quadra Island off Vancouver Island, Discovery Passage, British...

Doug Perrine / Spiny / Piked dogfish {Squalus acanthias} with Red sea urchins {Strongylocentrotus franciscanus} Quadra Island off Vancouver Island, Discovery Passage, British Columbia, Canada. Note - also known as...

GEORGETTE DOUWMA / Purple sea urchins {Strongylocentrotus purpuratus} in tide pool at low tide, Tongue Point, Washington, USA.

Norbert Wu / Wolf Eel (Anarrhichthys ocellatus) feeds on Crabs and Purple Sea Urchins (Strongylocentrotus purpuratus) six feet long, Monterey, California

Norbert Wu / White Sea Urchin (Lytechinus anamesus) group attack and feed on a larger Red Sea Urchin (Strongylocentrotus franciscanus), southern California

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus) group feeds on algae, southern California

Norbert Wu / Bat Star (Asterina miniata) surrounded by Purple Sea Urchins (Strongylocentrotus purpuratus) in Urchin Barrens, San Diego, California

Norbert Wu / Garibaldi (Hypsypops rubicundus) males defend algal nest by removing grazing Purple Sea Urchin (Strongylocentrotus purpuratus), southern California

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus) group feeding on Kelp (Macrocystis pyrifera) plants at base, killing entire 100 foot plant, San Diego, California

Norbert Wu / Garibaldi (Hypsypops rubicundus) male removes algae grazing Purple Sea Urchin (Strongylocentrotus purpuratus) from algal nest, southern California

Norbert Wu / Purple Sea Urchin (Strongylocentrotus purpuratus) barrens, population explosion destroys once lush Kelp forest, southern California

Jeff Rotman / Colony of Purple sea urchin {Strongylocentrotus purpuratus} feeding on kelp, California, USA

Jeff Rotman / Green Sea Urchin {Stronglyocentrotus droebachiensiss} feeding

Jeff Rotman / Purple sea urchin underside showing mouth. Pacific Channel islands, California

Jeff Rotman / Purple sea urchins {Strongylocentrotus purpuratus} feeding on kelp, Pacific, California, USA

Jeff Rotman / Green sea urchin (Strongylocentrotus droebachiensis) feeds on algae. North Atlantic

Ralph Pace / Purple Sea Urchin (Strongylocentrotus purpuratus) group creating urchin barren by feeding on kelp, Carmel, California

Jaymi Heimbuch / Western Gull (Larus occidentalis) feeding on Purple Sea Urchin (Strongylocentrotus purpuratus) prey, Yaquina Head Outstanding Natural Area, Newport, Oregon

Richard Herrmann / Red Sea Urchin (Strongylocentrotus franciscanus) group feeding on Giant Kelp (Macrocystis pyrifera) creating urchin barren, Santa Cruz Island, Channel Islands, California

Richard Herrmann / Purple Sea Urchin (Strongylocentrotus purpuratus) and Brittle Stars (Ophiothrix spiculata), Santa Cruz Island, Channel Islands, California

Jeff Rotman / Purple sea urchin {Strongylocentrotus purpuratus} Channel Is, California, USA

Terry Whittaker / Tracking shot of Arctic fox (Vulpes lagopus) male walking along rocky beach with Green sea urchin (Strongylocentrotus droebachiensis) in mouth, Hornstrandir Nature Reserve, Iceland. February.

Terry Whittaker / Arctic fox (Vulpes lagopus) male feeding on Green sea urchin (Strongylocentrotus droebachiensis) on rocky beach, Hornstrandir Nature Reserve, Iceland. February.

Russell Laman / California sea lions (Zalophus californianus) swimming over rock covered in Bat stars (Patiria miniata) and Pacific purple sea urchins (Strongylocentrotus purpuratus) near the Monterey Coast Guard Pie...

Russell Laman / Giant spined star (Pisaster giganteus) on a rock alongside Pacific purple sea urchins (Strongylocentrotus purpuratus) underneath a Giant kelp (Macrocystis pyrifera) forest off the coast of Monterey, C...

Russell Laman / Pacific purple sea urchins (Strongylocentrotus purpuratus) feeding on Giant kelp (Macrocystis pyrifera) on seabed, Monterey, California, USA, Pacific Ocean.

Russell Laman / Pacific purple sea urchins (Strongylocentrotus purpuratus) and Strawberry anemones (Actinia fragacea) covering rocks on seabed, Monterey, California, USA, Pacific Ocean.

Russell Laman / California sea lions (Zalophus californianus) swimming over rocks covered in Pacific purple sea urchins (Strongylocentrotus purpuratus) and Strawberry anemones (Actinia fragacea), Monterey, California...

Shane Gross / Red sea urchins (Strongylocentrotus franciscanus) gathered on the seabed, Barkley Sound, Vancouver Island, British Columbia, Canada.

Shane Gross / Purple sea urchins (Strongylocentrotus purpuratus) and Red sea urchins (Strongylocentrotus franciscanus) on seabed, Barkley Sound, Vancouver Island, British Columbia, Canada.

Shane Gross / Noble dorid (Peltodoris nobilis) resting on rocks surrounded by Sea urchins (Strongylocentrotus sp.) and Orange sea cucumbers (Cucumaria miniata), Barkley Sound, Vancouver Island, British Columbia, Ca...

Shane Gross / Underwater seascape showing Sunflower sea star (Pycnopodia helianthoides), Orange sea cucumbers (Cucumaria miniata) and Sea urchins (Strongylocentrotus sp.), Barkley Sound, Vancouver Island, British C...

Shane Gross / Sea urchins (Strongylocentrotus sp.) feeding on algae growing on a plastic milk crate left on the seabed, Barkley Sound, Vancouver Island, Canada.

Shane Gross / RF - Giant Pacific octopus (Enteroctopus dofleini) camouflaged among rocks with Sea urchins (Strongylocentrotus sp.) and Orange sea cucumbers (Cucumaria miniata), Barkley Sound, Vancouver Island, Brit...

Tony Wu / Male intermediate sea urchin (Strongylocentrotus intermedius) starting process of broadcast spawning. Pacific Ocean, Hokkaido, Japan.

Tony Wu / Male intermediate sea urchin (Strongylocentrotus intermedius) starting process of broadcast spawning. Pacific Ocean, Hokkaido, Japan.

David Hall / American lobster (Homarus americanus) with one larger claw, modified for crushing mollusk shells, while the other is designed for tearing or cutting softer prey, surrounded by Green urchins (Strongylo...

Shane Gross / Red sea urchin (Strongylocentrotus franciscanus) close up detail of spines and tube feet, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Shane Gross / Red sea urchin (Strongylocentrotus franciscanus) close up detail of spines, Browning Pass, Queen Charlotte Strait, Vancouver Island, British Columbia, Canada.

Shane Gross / Painted anemone (Urticina crassicornis) eating a Red sea urchin (Strongylocentrotus franciscanus) on rock wall, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Tony Wu / Intermediate sea urchins (Strongylocentrotus intermedius) spawning in the evening. The orange urchin is female, which releases eggs after detecting sperm that has been released by males, Hokkaido, Jap...

Tony Wu / Intermediate sea urchins (Strongylocentrotus intermedius) spawning in the evening. The orange urchin is female, which releases eggs after detecting sperm that has been released by males, Hokkaido, Jap...

Tony Wu / Male Intermediate sea urchins (Strongylocentrotus intermedius) commencing the spawning process by emitting sperm into the water, Hokkaido, Japan, Pacific Ocean.

David Hall / Marine invertebrates including Crimson anemones (Cribrinopsis fernaldi), Painted anemones (Urticina crassicornis), Red soft coral (Gersemia rubriformis), Red sea urchins (Strongylocentrotus franciscan...

David Hall / Puget sound king crab (Lopholithodes mandtii) and Red sea urchins (Strongylocentrotus franciscanus), Deserter Group, Queen Charlotte Strait, British Columbia, Canada. September.