Alex Mustard / Portrait of a Yellow seahorse (Hippocampus guttulatus), Capo Galera, Alghero, Sardinia, Italy, Mediterranean Sea.

Alex Mustard / A male Yellow-headed jawfish (Opistognathus aurifrons) blowing out a clutch of eggs he has been incubating in his mouth in order to oxygenate them, East End, Grand Cayman, Cayman Islands, British West...

Alex Mustard / 2020VISION / Amphipod (Iphimedia obesa) on top of a colony of Deadman's fingers (Alcyonium digitatum) coral, Loch Carron, Ross and Cromarty, Scotland, UK, April. Highly commended in the British Wildlife Photograph...

Claudio Contreras / French Angelfish (Pomacanthus paru) with a Smallmouth Grunt (Haemulon chrysargyreum) and Blade Fire Coral (Millepora complanata). Cancun National Park, Caribbean Sea, Mexico.

Alex Mustard / Yellow tube sponge (Aplysina fistularis) top view of tubes with water swirling around them, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Sand diver (Synodus intermedius) portrait on a coral reef, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Schoolmaster snapper (Lutjanus apodus) school, under a coral ledge, Snapper Hole, East End, Grand Cayman, Cayman Islands, Caribbean Sea.

Alex Mustard / Peacock flounder (Bothus lunatus) resting on the seabed, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Rock beauty angelfish (Holacanthus tricolor) pair at dusk performing their courtship dance with the larger male circling the female, Georgetown, Grand Cayman, Cayman Islands, British West Indies. Cari...

Alex Mustard / Schoolmaster snapper (Lutjanus apodus) above a coral reef, Georgetown, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Bluestriped grunt (Haemulon sciurus) portrait, West End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Yellowhead wrasse (Halichoeres garnoti) male performing a courtship dance to attract females, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Yellow goatfish (Mulloidichthys martinicus) swimming above the reef, West End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / Secretary blenny (Acanthemblemaria maria) making a home in a deserved worm tube of a great star coral (Montastraea cavernosa), East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Se...

Pedro Narra / Bottlenose dolphin (Tursiops truncatus) leaping in front of a cargo ship, Sado Estuary, Portugal, September

Linda Pitkin / 2020VISION / Black brittlestar (Ophiocomina nigra), yellow colour variety, with Common brittlestars (Ophiothrix fragilis), on sea bed, St Abbs (St Abbs and Eyemouth Voluntary Marine Reserve), Berwickshire, Scotlan...

Andy Rouse / Landscape of Seven Islands and arctic coastline. Svalbard, Norway, May 2010.

Roberto Rinaldi / Yellow fan coral / Seafan (Paramuricea clavata) amongst mass of invasive algae (Caulerpa taxifolia) with Rainbow wrasse fish (Coris julis), Strait of Messina, Southern Italy

Jeff Rotman / Close-up of scales of the Yellowbar Angelfish (Pomacanthus maculosus). Red Sea, Egypt.

Alex Mustard / 2020VISION / Light-bulb sea squirts (Clavelina lepadiformis), a colonial filter feeding invertebrate, fluoresce orange when photographed under deep blue light. Shetland Islands, Scotland, UK, June. Did you know? L...

Jeff Rotman / Yellow tube sponge (Aplysina fistularis) Red Sea, Egypt

Doug Perrine / Green sea turtle (Chelonia mydas) being cleaned of algae by Yellow tangs / surgeonfish (Zebrasoma flavescens), Puako, Kona, Hawaii, USA, June, Endangered species

Doug Perrine / Green sea turtle (Chelonia mydas) cleaned of algae by Yellow tangs / surgeonfish (Zebrasoma flavescens), Puako, Kona, Hawaii, USA, June, Endangered species

Juergen Freund / Golden sea squirt (Polycarpa aurata) West New Britain, Papua New Guinea.

Juergen Freund / Eyed / Leopard sea cucumber (Bohadschia argus), close-up of the skin. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Dugong (Dugong dugon) in the seagrass bed shadowed by a trevally. Dimakya Island, Palawan, Philippines

Juergen Freund / Star shaped Pincushion / Pillow cushion starfish (Culcita novaeguinea), detail of the underbelly. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Dugong (Dugong dugon) surfacing to take a breath of air. Dimakya Island, Palawan, Philippines.

Juergen Freund / Star shaped Pincushion / Pillow cushion starfish (Culcita novaeguinea), detail of the underbelly. Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Sea pen octocoral (Veretillum sp) with polyps out, feeding, Misool, Raja Ampat, West Papua, Indonesia

Juergen Freund / Schooling Banggai cardinalfish in anemone tentacles. (Pterapogon kaudemi). Lembeh Strait, North Sulawesi, Indonesia

Juergen Freund / Golden damselfish (Amblyglyphidodon aureus) swimming around a fan coral. Misool, Raja Ampat, West Papua, Indonesia

Alex Mustard / A female Spiny Seahorse (Hippocampus guttulatus) in weeds. Sardina, Gran Canaria, Canary Islands, East Atlantic Ocean, October.

Juergen Freund / Dugong (Dugong dugon) feeding in the seagrass bed with trevally fish inspecting the disturbed sand. Dimakya Island, Palawan, Philippines

Juergen Freund / Estuary / Spotted / Common seahorse (Hippocampus kuda) in the rubble. Lembeh Strait, Sulawesi, Indonesia

Floris van Breugel / Burrowing Owl (Athene cunicularia) standing at entrance to burrow, and watching a Red-tailed Hawk circling above. Salton Sea, California, USA.

Floris van Breugel / Burrowing Owls (Athene cunicularia) breeding pair standing near the entrance to their burrow, at sunset, Salton Sea, California, USA.

Tim Laman / Denise's Pygmy seahorse (Hippocampus denise) camouflaging itself in a Sea Fan. Yellow colour form. Pisang Islands, West of Fak Fak Peninsula. West Papua, Indonesia, April 2007

Doug Perrine / Dolphin fish / Mahi mahi / Dorado (Coryphaena hippurus) large male, off Isla Mujeres, near Cancun, Yucatan Peninsula, Mexico, Caribbean Sea

Sue Daly / Lightbulb seasquirts / tunicates (Clavelina lepadiformis) cluster on rock, Channel Isles, UK, July

Uri Golman / Sunset over iceberg. Jakobshavn, Ilulissat, Kangia, Icefjord, Greenland. August 2006.

Wild Wonders of Europe / Banfi / Male Yellow triplefin blenny (Tripterygion delaisi) Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Wild Wonders of Europe / Banfi / Keys simnia (Neosimnia spelta) on a Yellow gorgonia (Eunicella cavolini) Larvotto Marine Reserve, Monaco, Mediterranean Sea, July 2009

Claudio Contreras / Cushion sea star (Oreaster reticulatus) on Turtle grass (Thalassia testudinum) Banco Chinchorro Biosphere Reserve, Caribbean Sea, Mexico, July

Wild Wonders of Europe / Pitkin / Gorgonian coral (Paramuricea clavata) on rock face covered with Yellow encrusting anemones (Parazoanthus axinellae) sponges and corals, 'Horsehead', Lavezzi Islands, Corsica, France, September 2008

Wild Wonders of Europe / Cairns / Silver birch (Betula verrucosa) trunk in sea of Eurasian dwarf cornel (Cornus suecica) Sarek National Park, Laponia World Heritage Site, Lapland, Sweden, September 2008

Georgette Douwma / Yellow Boxfish / Cube trunkfish (Ostracion cubicus) Egypt, Red Sea.

Birgitte Wilms / Nudibranch laying eggs, Indonesia

Ingo Arndt / Antarctic Krill (Euphausia superba) with yellow algae in stomach, a small shrimp-like crustacean is the most important zooplankton in the Antarctic food web, Weddell Sea, Antarctica

Peter Scoones / Yellow / Goldsaddle goatfish (Parupeneus cyclostomus) hunting together with Bluefin Jacks (Caranx melampygus) and Chinese sea kraits {Laticauda semifasciata} over coral reef, Gunung Api, Banda sea, In...

Doug Perrine / Yellow tube sponge {Aplysina fistularis} with Yellowtail snappers {Ocyurus chrysurus Cayman Brac, Cayman Islands, Caribbean

Chris Newbert / Scarlet Cleaner Shrimp (Lysmata amboinensis) pair cleaning a Moray Eel (Gymnothorax ocellatus) 80 feet deep, Solomon Islands

Norbert Wu / Green Sea Turtle (Chelonia mydas) being cleaned by Yellow-eyed Surgeonfish (Ctenochaetus strigosus), Hawaii

Chris Newbert / Yellow-striped Cardinalfish (Apogon cyanosoma) male with eggs in mouth, 40 feet deep, Solomon Islands

Chris Newbert / Soft Coral (Dendronephthya sp) schooling Pygmy Sweeper (Parapriacanthus ransonneti) and Lionfish (Pterois volitans)

Chris Newbert / Fan Coral (Melithaea sp) group and Feather Star (Oxycomanthus bennetti), Solomon Islands

Chris Newbert / Hermit Crab (Paguritta gracilipes) in Hump Coral (Porites sp) 30 feet deep, Solomon Islands

Norbert Wu / Green Sea Turtle (Chelonia mydas) being cleaned by reef fish, Hawaii

Chris Newbert / Pygmy Sweeper (Parapriacanthus ransonneti) in cave

Chris Newbert / Pygmy Sweeper (Parapriacanthus ransonneti) school in cave, Red Sea, Egypt

Chris Newbert / Soft Coral (Dendronephthya sp) outcroppings, Sea Fan (Subergorgia sp) and Glassfish (Parapriacanthus ransonneti)

Fred Bavendam / Long-snouted Seahorse (Hippocampus reidi) portrait, Bonaire, Netherland Antilles

Fred Bavendam / Banded Sea Krait (Laticauda colubrina) hunting for small fish on the reef, Manado, North Sulawesi, Indonesia

Fred Bavendam / Feather Star (Oxycomanthus bennetti) clinging to a coral prominence where it can feed in the currents, Milne Bay, Papua New Guinea

Francis Abbott / Two Bar Anemonefish, Red Sea. (Amphiprion bicinctus)

Georgette Douwma / Two Golden / Masked butterflyfish, Red Sea, Eygpt

Georgette Douwma / Golden damselfish juveniles {Amblyglyphidodon aureus} with coral. Andaman sea, Thailand

David Tipling / Emperor Penguins, (Aptenodytes forsteri), family, Weddell Sea, Antarctica

Juan Carlos Munoz / Melting ice on Jokulsarlon beach. Southern Iceland, Europe, November 2012.

Sue Daly / Jewel Anemones (Corynactis viridis). Pavlaison, Sark, British Channel Islands, July.

Sue Daly / Jewel Anemones (Corynactis viridis). Pavlaison, Sark, British Channel Islands, July.

Sue Daly / Jewel Anemones (Corynactis viridis). Pavlaison, Sark, British Channel Islands, July.

Nick Upton / Atlantic Yellow legged gull (Larus michahellis) calling as it stands on sandstone cliff with the sea in the background, Praia da Rocha, Algarve, Portugal, June.

Nick Upton / Atlantic Yellow legged gull (Larus michahellis) calling as it stands on sandstone cliff nest site near its chick with a wave washed beach in the background, Praia da Rocha, Algarve, Portugal, June.

Ross Hoddinott / Sea and stones at Porth Nanven beach, with rising tide at sunset, The Cot Valley, near Cape Cornwall, West Cornwall, UK. September 2012.

Alex Mustard / A female Yellow seahorse (Hippocampus guttulatus), Capo Galera, Alghero, Sardinia, Italy, Mediterranean Sea.

Alex Mustard / Portrait of a Longsnout seahorse (Hippocampus reidi) gripping onto a small Sea rod (Pseudoplexaura) with its prehensile tail, West Bay, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea...

Marie Read / Yellow-footed Gull (Larus livens) with its fish prey by water. Salton Sea National Wildlife Refuge, California, USA, October.

Marie Read / Yellow-footed Gull (Larus livens). carrying a large fish, on beach at the Salton Sea. Salton Sea National Wildlife Refuge, California, USA, October.

Christophe Courteau / Warty nudibranch {Doris verrucosa} Brittany France

Georgette Douwma / Longnose butterflyfish (Forcipiger longirostris). Andaman Sea, Thailand.

David Pattyn / Yellow flag iris (Iris pseudacorus) in a lake, Texel Island, Wadden Sea, The Netherlands June

Tui De Roy / Yellow warbler (Dendroica petechia) female in shoreline manzanillo tree just after bathing in sea water, Playa Ochoa, San Cristobal Island, Galapagos Islands, Ecuador, June.

Alex Mustard / 2020VISION / Amphipod (Iphimedia obesa) on top of a colony of Deadman's fingers (Alcyonium digitatum) coral, Loch Carron, Ross and Cromarty, Scotland, UK, April.

Alex Mustard / 2020VISION / Amphipod (Iphimedia obesa) on top of a colony of Deadman's fingers (Alcyonium digitatum) coral, Loch Carron, Ross and Cromarty, Scotland, UK, April.

Alex Mustard / 2020VISION / Amphipod (Iphimedia obesa) on top of a colony of Deadman's fingers (Alcyonium digitatum) coral, Loch Carron, Ross and Cromarty, Scotland, UK, April. Did you know? Although coral reefs are thought of a...

Solvin Zankl / GEOMAR / Barbara Lich editor from GEOlino and Solvin Zankl inside the submersible JAGO. Solvin Zankl is photographing cold water corals on board RV POSEIDON for three weeks, going down to 200m to visit the Sul...

Solvin Zankl / GEOMAR / Submersible JAGO on board RV POSEIDON at the Sula Reef in Norway, this submersible can dive to 400m and hold a pilot and observer, September 2011, editorial use only. Photo taken in cooperation with G...

Georgette Douwma / Yellow sea cucumber (Colochirus robustus) feeding, Rinca, Komodo National Park, Indonesia

Linda Pitkin / 2020VISION / John dory (Zeus faber), with Sea thong (Himanthalia elongata) in the background, Porthkerris Cove, Cornwall, England, UK, June

Brent Stephenson / Atlantic yellow-legged gull (Larus michahellis atlantis) picking food from the surface of the sea whilst in flight. Off Madeira, North Atlantic. May.

Ernie Janes / Storm clouds over Oilseed rape in flower, towards Blakeney Point and the North sea, Norfolk, UK, April

Sue Daly / Yellow cluster anemones (Parazoanthus axinellae) Channel Islands, UK May

Richard Herrmann / Giant Kelp (Macrocystis pyrifera) blades floating at surface, Cortez Bank, California