David Fleetham / Hawksbill Turtle (Eretmochelys imbricata) and a shoal of fish near sea surface. Tubbataha Reef, Philippines.

Chase Dekker / Humpback Whale (Megaptera novaeangliae) calf breaching, Monterey Bay, California

Chase Dekker / Humpback Whale (Megaptera novaeangliae) calf breaching, Monterey Bay, California

Chase Dekker / Humpback Whale (Megaptera novaeangliae) calf breaching, Monterey Bay, California

Chase Dekker / Humpback Whale (Megaptera novaeangliae) breaching at sunset, Monterey Bay, California

Chase Dekker / Humpback Whale (Megaptera novaeangliae) breaching, Monterey Bay, California

Danny Green / Polar bear (Ursus maritimus) walking across sea ice, reflected in water. Svalbard, Norway, July.

Alex Mustard / Spinner dolphin (Stenella longirostris) pod socialising close to surface. Fury Shoal, Sataya Reef, Marsa Alam, Egypt.

Alex Mustard / Oceanic whitetip shark (Carcharhinus longimanus) swimming close to surface. Brothers Islands, Egypt.

Oscar Dewhurst / Mute swan (Cygnus olor) swimming with cygnets in misty lake in morning light. Richmond Park, London, England, UK. May.

Guy Edwardes / Dalmatian pelican (Pelecanus crispus), portrait. Lake Kerkini, Sintik, Greece. January.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) male calf playing at ocean surface after coming up to breathe. Vava'u Islands, Tonga.

Ingo Arndt / Sun rising over ice formations on Lake Baikal. Siberia, Russia. February 2019.

Gary Bell/ Oceanwide / Humpback Whale (Megaptera novaeangliae) breaching, Tonga

George Sanker / Great egret (Ardea alba) with prey in beak, in evening light. Myakka River State Park, Florida, USA, March. Sequence 2/2.

George Sanker / Great egret (Ardea alba) diving head into water to catch prey, in evening light. Myakka River State Park, Florida, USA, March. Sequence 1/2.

Jordi Chias / Antarctic fur seal (Arctocephalus gazella), Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) spyhopping, Antarctic Peninsula, Antarctica.

Jordi Chias / Gentoo penguins (Pygoscelis papua) swimming together and porpoising in search of krill, Antarctic Peninsula, Antarctica.

Jordi Chias / Gentoo penguins (Pygoscelis papua) porpoising, swimming together in search of krill, Antarctic Peninsula, Antarctica.

Jordi Chias / Leopard seal (Hydrurga leptonyx) predating a Gentoo penguin (Pygoscelis papua) Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) fluke Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) diving, tail fluke, Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae), adult and baby at surface, Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) surfacing with baby and blowing, Antarctic Peninsula, Antarctica.

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 / North Pacific humpback whale (Megaptera novaeangliae kuzira) breaching, Icy Strait, Alaska, USA. July.

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 / Killer whales (Orcinus orca) at the surface in an Arctic fjord in Spildra, northern Norway, with sea birds. Arctic Ocean

Alex Mustard / Blue whale (Balaenoptera musculus) swimming beneath the surface of the ocean. Indian Ocean, off Sri Lanka.

Alex Mustard / Blue whale (Balaenoptera musculus) swims beneath the surface of the ocean. Indian Ocean, off Sri Lanka.

Alex Mustard / Pod of False killer whales (Pseudorca crassidens) swimming beneath the surface of the ocean. Indian Ocean, off Sri Lanka.

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

Nigel Cattlin / Harlequin ladybird (Harmonia axyridis) larvae still with a raft of empty egg cases, June Berkshire, England, UK.

Milan Radisics / Aerial shot of rootless cones or pseudocraters, formed by steam explosions as flowing hot lava crosses over a wet surface, South Iceland, August 2018.

Espen Bergersen / Humpback whales (Megaptera novaeangliae) showing tail fluke when they dive. Kvanangen, Troms, Norway. December

Espen Bergersen / Humpback whale (Megaptera novaeangliae) feeding around herring fishing vessel. Kvanangen, Troms, Norway. November

Espen Bergersen / Humpback whale (Megaptera novaeangliae) diving. In background a diving boat and 3 divers visible in the water. Kvanangen, Troms, Norway. November

Espen Bergersen / Aerial view of Fin whale (Balaenoptera physalus). Kvanangen, Troms, Norway. November

Espen Bergersen / Sperm whale {Physeter macrocephalus} showint tail fluke as it dives. Photographed just before midnight. 22 nautical miles northwest of Andenes, Northern Norway. July

Espen Bergersen / Killer whale / orca (Orcinus orca). Spyhopping very close, showing eye. Kvanangen, Troms, Norway. November

Espen Bergersen / Humpback whale (Megaptera novaeangliae) showing tail fluke as it dives. Kvanangen, Troms, Norway. November

Espen Bergersen / Killer whales / orcas (Orcinus orca) and boat in background. Kvanangen, Troms, Norway. November

Espen Bergersen / Humpback whales (Megaptera novaeangliae). Kvanangen, Troms, Norway. November

Espen Bergersen / Herring (Clupea harengus) caught in fishing net. Gulls in the net are taking of and flying around, shot with long shutter speed. Norway. December. November

Espen Bergersen / Killer whales / orcas (Orcinus orca). Spyhopping. Kvaloya, Troms, Norway November

Espen Bergersen / Killer whales / orcas (Orcinus orca). Spyhopping. Kvaloya, Troms, Norway October

Espen Bergersen / Killer whales / orcas (Orcinus orca). Spyhopping. Kvaloya, Troms, Norway October

Espen Bergersen / Killer whale / orca (Orcinus orca) splashing with tail fluke. Kvaloya, Troms, Norway October Sequence 4 of 7

Espen Bergersen / Gulls and Killer whales / orcas (Orcinus orca) feeding on herring. Kvaloya, Troms, Norway October

Espen Bergersen / Killer whales / orcas (Orcinus orca) two spyhopping. Kvaloya, Troms, Norway October

Espen Bergersen / Killer whales / orcas (Orcinus orca) two spyhopping. Kvaloya, Troms, Norway October

Espen Bergersen / Killer whale / orca (Orcinus orca) male. Kvaloya, Troms, Norway October

Espen Bergersen / Long-finned Pilot Whale (Globicephala melas) spyhopping, Andfjorden, Andoya, Norway. July

Espen Bergersen / Killer whales / orcas (Orcinus orca) feeding on a bait ball of Herring. Extremely cold conditions (- 15 C) with backlit ice fog. Kvanangen, Troms, Norway. January

Espen Bergersen / Humpback whale (Megaptera novaeangliae) showing tail fluke as it dives. Kvanangen, Troms, Norway. December

Doc White / Sea Otter, (Enhydra lutris), young male, Elkhorn Slough, California, USA. January

Nick Hawkins / North Atlantic right whale (Eubalaena glacialis) tail fluke, diving to feed in the Gulf of Saint Lawrence, Canada. Endangered species. July

Nick Hawkins / Aerial view of Carter's Beach on the Southshore of Nova Scotia, Canada. August

Nick Hawkins / Steller's sea lions (Eumetopias jubatus) off the coast of the Great Bear Rainforest, near Bella Bella, British Columbia, Canada. August

Nick Hawkins / Fishing ropes wrap around the head and mouth, damaging the baleen of a severely entangled North Atlantic right whale (Eubalaena glacialis) in the Gulf of Saint Lawrence, Canada. Fishing gear entanglem...

Nick Hawkins / Fishing ropes wrap over the blowhole of a severely entangled North Atlantic right whale (Eubalaena glacialis) in the Gulf of Saint Lawrence, Canada. Fishing gear entanglement is a leading cause of dea...

Nick Hawkins / Head of a North Atlantic right whale (Eubalaena glacialis) showing callosities, patches of roughened skin that are unique to each whale. Gulf of Saint Lawrence, Canada. IUCN Status: Endangered. August

John Chan / California sea lion (Zalophus californianus) feeding on a Striped bass (Morone saxatilis), Southern California, USA.

SCOTLAND: The Big Picture / Common dolphin (Delphinus delphis) jumping out the water, Shetland, Scotland, UK, January.

SCOTLAND: The Big Picture / Orca whales (Orcinus orca) pod surfacing together, Shetland, Scotland, UK. April.

SCOTLAND: The Big Picture / Orca (Orcinus orca) surfacing and blowing, Shetland, Scotland, UK, August.

SCOTLAND: The Big Picture / Northern gannets (Morus bassanus) diving for fish, split level shot, Shetland, Scotland, UK, September.

Espen Bergersen / Aerial shot of three Killer whales (Orcinus orca) swimming close to the surface, Troms, Norway, August.

Espen Bergersen / Aerial shot of Killer whales (Orcinus orca) near the surface, showing mating behaviour including a male Killer whale displaying penis, Troms, Norway, August.

Espen Bergersen / Aerial shot of Killer whales (Orcinus orca) near the surface, showing mating behaviour, Troms, Norway, August.

Espen Bergersen / Aerial shot of a pod of Killer whales (Orcinus orca) swimming near the surface, Troms, Norway, October.

Espen Bergersen / Aerial shot of four Humpback whales (Megaptera novaeangliae) swimming near to a shoal of Atlantic herring (Clupea harengus), Troms, Norway, January.

Espen Bergersen / Aerial shot of a Humpback whale (Megaptera novaeangliae) swimming showing belly, Troms, Norway, January.

Espen Bergersen / Aerial shot of a Humpback whale (Megaptera novaeangliae) showing belly and blowing, Troms, Norway, January.

Espen Bergersen / Aerial shot of a large group of Humpback whales (Megaptera novaeangliae), Troms, Norway, January.

Espen Bergersen / Aerial shot of a large group of Humpback whales (Megaptera novaeangliae), Troms, Norway, January.

Espen Bergersen / Aerial shot of two Humpback whales (Megaptera novaeangliae) coming to the surface to breathe, Sommaroy, Troms, Norway, January.

Espen Bergersen / Aerial shot of Killer whale (Orcinus orca) carousel feeding close to Tromvik harbour, Troms, Norway, December.

Espen Bergersen / Aerial shot of Killer whale (Orcinus orca) hunting Atlantic herring (Clupea harengus) using carousel feeding, with herring jumping out of the water and gulls (Larus) circling above, Tromvik, Troms, No...

Espen Bergersen / Aerial shot of a small pod of Killer whales (Orcinus orca) at surface, with snowy landscape in the background, Skjervoy, Troms, Norway, December.

Espen Bergersen / Aerial shot of a pod of Killer whales (Orcinus orca) carousel feeding, Skjervoy, Troms, Norway, November.

Espen Bergersen / Aerial shot of a pod of Killer whales (Orcinus orca) carousel feeding, Skjervoy, Troms, Norway, November.

Espen Bergersen / Aerial shot of a pod of Killer whales (Orcinus orca) carousel feeding, drone moving closer, Skjervoy, Troms, Norway, November.

Marie Read / Western Grebe (Aechmorphus occidentalis), pair during 'rushing' courtship display in which they run across water's surface in synchrony, near Escondido, California, USA, January.

Mark Carwardine / Aerial view Fin whales (Balaenoptera physalus) lunge-feeding in the southern Sea of Cortez (Gulf of California), Baja California, Mexico.

Mark Carwardine / Aerial view of Fin whale (Balaenoptera physalus) lunge-feeding, with throat pouch distended, southern Sea of Cortez (Gulf of California), Baja California, Mexico.

Mark Carwardine / Aerial view Fin whales (Balaenoptera physalus) lunge-feeding in the southern Sea of Cortez (Gulf of California), Baja California, Mexico.

Mark Carwardine / Aerial view Fin whales (Balaenoptera physalus) lunge-feeding in the southern Sea of Cortez (Gulf of California), Baja California, Mexico.

Franco Banfi / Water lilies at the surface in Cenote Nicte-Ha,Tulum, Quintana Roo, Yucatan Peninsula, Mexico.

Franco Banfi / Water lilies at the surface in Cenote Nicte-Ha,Tulum, Quintana Roo, Yucatan Peninsula, Mexico.

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

Markus Varesvuo / White-fronted goose (Anser albifrons) and Taiga bean goose (Anser fabalis rossicus) flocks in flight and on water. Latvia. April.

George Sanker / North American river otter (Lontra canadensis) swimming with head above water. Acadia National Park, Maine, USA. November.

David Fleetham / Humpback whale (Megaptera novaeangliae) breaching, watched by paddle boarder. Canoe Beach, Maui. Hawaii. October 2010. Model released. Digital composite.

Stefan Christmann / Orca (Orcinus orca), two spyhopping in gap in sea ice. Atka Bay, Antarctica. January.