Pascal Kobeh / False clown anemonefish (Amphiprion ocellaris) in a magnificent sea anemone (Heteractis magnifica), Sulu sea, Philippines

Doug Perrine / Dugong or Sea cow (Dugong dugon) split level view, Calauit Island, off Busuanga, Calamian Islands, Palawan, Philippines.

Tony Wu / Humpback whale (Megaptera novaeangliae) lying on its side while executing a series of pectoral fin slaps on ocean surface. Vava'u, Tonga, South Pacific.

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis) female nudging her mother's mammary gland whilst trying to feed. Vava;u, Tonga, South Pacific.

Alex Mustard / Split level image of Leather corals (Sarcophyton sp.) flourishing in shallow water close to uninhabited coral islands. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean...

Alex Mustard / Commensal emperor shrimp (Periclimenes imperator) moves across the colourful red patterned surface of its host Candycane sea cucumber (Thelenota rubralineata). Misool, Raja Ampat, West Papua, Indonesi...

Alex Mustard / Three Pink anemonefish (Amphiprion perideraion) living in a purple skirted magnificent sea anemone (Heteractis magnifica) on a coral reef, below a small island. Misool, Raja Ampat, West Papua, Indones...

Alex Mustard / California sea lion (Zalophus californianus) pups in an underwater cave. Los Islotes, La Paz, Baja California Sur, Mexico. Sea of Cortez, Gulf of California, East Pacific Ocean.

Alex Mustard / Whale shark (Rhincodon typus) close to the camera with a golden trevally fish (Gnathanodon speciosus) and outline of another whale shark behind , in the plankton-rich green waters of La Paz bay, Baja...

Alex Mustard / Orange painted frogfish (Antennarius pictus) fishing. Here the frogfish is illuminated by a snooted strobe and the background sand lit with a red LED torch. Bitung, North Sulawesi, Indonesia. Lembeh S...

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Free swimming mimic octopus (Thaumoctopus mimicus). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Thorny seahorse (Hippocampus histrix) gripping onto a sponge. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Pair of Western clown anemonefish (Amphiprion ocellaris) spawning orange eggs on the rock beneath their Magnificent sea anemone (Heteractis magnifica) home on a coral reef. This photo shows the larger...

Alex Mustard / Two female Common seahorses (Hippocampus kuda) fighting over territory on the seabed. The brief fight was preceeded by a ritualised, synchronised parade. Bitung, North Sulawesi, Indonesia. Lembeh Stra...

Alex Mustard / Common seahorse (Hippocampus kuda) female wrapping her prehensile tail around piece of wood on the seabed. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) shelters inside an old clam shell, with silver-sides in the water above. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Whitemargin stargazer (Uranoscopus sulphureus) sets an ambush in the sand at night. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) emerging from its home in an old clam shell. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Reef lizardifsh (Synodus variegatus) at a cleaning station, being cleaned by Holthuis anemone shrimps (Ancylomenes holthuisi). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Tony Wu / Blacktip reef shark (Carcharhinus melanopterus) beaching itself to catch sardines. Tonga South Pacific.

Tony Wu / Sardines (Clupeidae) fleeing from predators in the early morning. They were being herded and chased by Trevallies and Blacktip reef sharks in the water, and picked off by brown boobies and terns from...

Alex Mustard / Shoal of three Bigfin reef squid (Sepioteuthis lessoniana) in open water at night. Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Portrait of a Giant frogfish (Antennarius commersoni) on a large Yellow elephant ear sponge (Ianthella basta). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Alex Mustard / Coral (Lobophytum sp.) on a reef flat, with Hawksbill turtle (Eretmochelys imbricata) in background. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Alex Mustard / Hawksbill turtle (Eretmochelys imbricata) unusually feeding on hard coral polyps. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Alex Mustard / Blacktip reef shark (Carcharhinus melanopterus) swims through schools of fish. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

Alex Mustard / Green turtle (Chelonia mydas) descending after breathing at the surface. Misool, Raja Ampat, West Papua, Indonesia. Ceram Sea. Tropical West Pacific Ocean.

John Shaw / Great frigatebird (Fregata minor) male at nest site, with gular sac inflated to attract females. Genovesa Island, Galapagos, May.

Shane Gross / Larval flounder (possibly Laeops Kitahara) in the open ocean at night off Anilao, Philippines.

Shane Gross / Portrait of a Thorny seahorse (Hippocampus histrix) near Malapascua, Philippines.

Shane Gross / Pygmy seahorse (Hippocampus bargibanti) holding on to a branch of a sea fan coral. Malapascua, Philippines.

Shane Gross / Pelagic thresher shark (Alopias pelagicus) cleaned by a Bluestreak cleaner wrasse (Labroides dimidiatus) at Monad Shoal off Malapascua Island, Philippines.

Shane Gross / Pelagic thresher shark (Alopias pelagicus) being cleaned by a bluestreak cleaner wrasse (Labroides dimidiatus) at Monad Shoal off Malapascua Island, Philippines.

Shane Gross / Thorny or spiny seahorse (Hippocampus histrix) portrait made off Anilao, Philippines.

Shane Gross / Bubble coral shrimp (Vir philippinensis) on Bubble coral (Plerogyra sp). Anilao, Philippines.

Shane Gross / Larval Wonderpus octopus (Wunderpus photogenicus) drifting in the open ocean at night off Anilao, Philippines.

Shane Gross / Wonderpus octopus (Wunderpus photogenicus) in its juvenile or larval stage. At this stage it is transparent and drifts in the open ocean as plankton. Anilao, Philippines.

Shane Gross / Moorish idol (Zanclus cornutus) juvenile with transparent skin in the open ocean at night off Anilao, Philippines.

Shane Gross / A juvenile soldierfish, possibly a Crescent-tail bigeye (Priacanthus hamrur) in the open ocean at night off Anilao, Philippines.

Tui De Roy / Marine iguana (Amblyrhynchus cristatus), Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguanas (Amblyrhynchus cristatus) fighting, Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) group on rocks, Cape Douglas, Fernandina Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus), Punta Espinosa, Fernadina Island, Galapagos

Georgette Douwma / Shortfin lionfish (Dendrochirus brachypterus). Lembeh Strait, North Sulawesi, Indonesia.

Andy Rouse / Galapagos sea lion, (Zalophus wollebaeki), swimming upside down, Galapagos

Georgette Douwma / Nudibranch (Chromodoris willani) with a scale worm. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Ribbon eel ( Rhinomuraena quaesita) Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Colonial anemones (Amphianthus nitidus) with Green urn sea squirts (Didemnum molle) (Atriolum robustum). Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Corkscrew or Long tentacle anemone (Macrodactyla doreensis). Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Banggai cardinalfish (Pterapogon kauderni) with a Corkscrew or Long tentacle anemone (Macrodactyla doreensis). Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Thornback cowfish (Lactoria fornasini). Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Boxer Crab (Lybia tessellata) with sea anemones in its claws for defense. Lembeh Strait, North Sulawesi, Indonesia.

Georgette Douwma / Taylor's pygmy leatherjacket (Brachaluteres taylori). Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Moral eels, Urchins, Cuttlefish, Shrimp and other marine life living within a discarded tyre and fishing net under a ships' harbour, Maluku, Indonesia. November.

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) on shore, Punta Moreno, Isabela Island, Galapagos

David Gallan / Two Southern right whales (Eubalaena australis) playing in shallows, taken with drone, Tathra Beach, New South Wales, Australia, August.

Pascal Kobeh / Trumpetfish (Aulostomus chinensis) on the coral drop off, Sulu Sea, Philippines.

Franco Banfi / Striped marlin (Kajikia audax) hunting Sardine (Sardinops sagax) in bait ball. Magdalena Bay, Baja California Sur, Mexico.

Franco Banfi / Striped marlin (Tetrapturus audax) feeding on Sardine (Sardinops sagax). Magdalena Bay, Baja California Sur, Pacific Ocean, Mexico.

Denis-Huot / Clownfish (Amphiprion sp) in anemone home, Philippines.

Doug Perrine / Pacific leatherback sea turtle (Dermochelys coriacea) a critically endangered species, Kei ( or Kai ) Islands, Moluccas, eastern Indonesia, Banda Sea, Southwest Pacific Ocean

Nick Hawkins / Marine iguana (Amblyrhynchus cristatus) basking on volcanic rock at coast. Isabela Island, Galapagos.

Nick Hawkins / Galapagos green turtle (Chelonia mydas agassizi) swimming above sea floor with shoal of fish in background. Off San Cristobal Island, Galapagos.

David Fleetham / Bargibant's pygmy seahorse (Hippocampus bargibanti) wrapped around Eye fan coral (Cnidaria sp). Philippines.

David Fleetham / Ring-tailed cardinalfish (Ostorhinchus aureus), male protecting and incubating eggs in mouth, Philippines.

Tui De Roy / Galapagos lava lizard (Microlophus albemarlensis) sitting on Marine iguana (Amblyrhynchus cristatus) Punta Espinosa, Fernandina Island, Galapgos.

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) in water, Puerto Egas, Santiago Island, Galapagos

Tui De Roy / Marine iguanas (Amblyrhynchus cristatus) silhouettes at sunset, Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) males in breeding colouration on rocks, with sun halo, Floreana Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) group on rock in the waves, Cape Hammond, Fernandina Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) swimming underwater, Sullivan Bay, Santiago Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) in the surf, Black Beach, Floreana Island, Galapagos

Tui De Roy / Blue-footed booby (Sula nebouxii), group of eight diving into sea to fish. Punta Gavilanes, Fernandina Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii), group fishing underwater. Itabaca Channel, Santa Cruz Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii) diving towards sea, folding wings. Northeast coast, Santiago Island, Galapagos. Sequence 1/2.

Tui De Roy / Blue-footed booby (Sula nebouxii) coming in to land. Punta Vicente Roca, Isabela Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii) perched on rock at coast. Santa Fe Island, Galapagos. August 2015.

Tui De Roy / Blue-footed booby (Sula nebouxii), five diving into sea. Espumilla Beach, Santiago Island, Galapagos.

Alex Mustard / Remoras (Remora sp.) hitchhiking on the tail of a large (13-15m) female whale shark (Rhincodon typus) swims in open water. Wolf Island, Galapagos National Park, Galapagos Islands. East Pacific Ocean.

Alex Mustard / Galapagos green turtle (Chelonia mydas agassizii) swims over a coral reef. Darwin Island, Galapagos National Park, Galapagos Islands. East Pacific Ocean.

David Fleetham / Humpback whale (Megaptera novaeangliae), mother and calf swimming just below surface in front of the West Maui Mountains. South of Lahaina, West Maui, Hawaii.

David Fleetham / Whale shark (Rhincodon typus), a commercial encounter for tourists with feeder above on canoe. Oslob, Cebu, Philippines. April 2017.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female, stationary with calf heading to surface for breath of air. Vava'u, Tonga, South Pacific.

David Fleetham / Marine iguana (Amblyrhynchus cristatus) emerging from ocean into Mangroves (Rhizophoraceae). Santa Cruz Island, Galapagos, Ecuador.

David Fleetham / Tiny Whitespotted bamboo shark (Chiloscyllium plagiosum) formed inside egg casing, Philippines.

David Fleetham / Mouth of the worlds largest fish, the Whale shark (Rhincodon typus), Donsol, Philippines.

David Fleetham / Schooling Brown striped snapper (Xenocys jessiae) and Yellowtail sawtail (Prionurus laticlavius), Galapagos Islands, Ecuador.

David Fleetham / Close up of underside of Panamic cushion star (Pentaceraster cumungi), Galapagos Islands, Ecuador.

David Fleetham / Opening in the mantle of Giant clam (Tridacna gigas) Tubbataha Reef, Philippines.

David Fleetham / Clown anemonefish (Amphiprion ocellaris), Philippines.

David Fleetham / White-eyed moray eel (Muraena thyrsoides) close to Zebra lionfish (Dendrochirus zebra), Philippines.

David Fleetham / Striped triplefin (Helcogramma striata) on hard coral, Tubataha Reef, Philippines.