Ismaele Tortella / Eurasian otter (Lutra lutra) hunting in a shoal of Atlantic herring (Clupea harengus), northern Norway, March

Diane McAllister / Polar bears (Ursus maritimus) fighting in water. Beaufort Sea , Kaktovik, Alaska, USA. Highly commended in the Polar Passion category of the Nature's Best Photography Competition 2019.

Alex Mustard / Yellowtail tang (Zebrasoma xanthurum) male and female turn belly to belly during spawning to ensure fertilization. Temple, Ras Umm Sid, Sharm El Sheikh, Sinai, Egypt. Red Sea. This action is very fast...

Claudio Contreras / Californian sea lion (Zalophus californianus) swimming in Southern sea palm (Eisenia arborea) and Giant Kelp (Macrocystis pyrifera) forest, San Benitos Islands, Baja California Pacific Islands Biosphe...

Sergio Hanquet / Arrow crab (Sternorhynchus lanceolatus). Tenerife, Canary Islands.

Sergio Hanquet / Green sea turtle (Chelonia mydas), two viewed from above. Tenerife, Canary Islands.

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

Danny Green / Polar bear (Ursus maritimus) and cubs, standing on sea ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs resting on sea ice. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) female and cubs, one cub walking up slope of ice in foreground. Svalbard, Norway, July.

Danny Green / Polar bear (Ursus maritimus) and cubs feeding on Whale carcass, on iceberg. Svalbard, Norway, July 2018.

Danny Green / Ringed seal (Pusa hispida) and pup resting on ice. Svalbard, Norway. April.

Danny Green / Polar bear (Ursus maritimus) resting on sea ice, view from above. Svalbard, Norway, June 2018.

Danny Green / Polar bear (Ursus maritimus) hunting Seal on sea ice. Svalbard, Norway, July 2018.

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

Danny Green / Polar bear (Ursus maritimus), two cubs walking on sea ice. Svalbard, Norway, July.

Danny Green / Ringed seal (Pusa hispida) resting on ice, reflected in water. Svalbard, Norway. July.

Nick Garbutt / Black-browed albatross (Thalassarche melanophris) flying over South Atlantic. Cooper Bay, South Georgia. November.

Tony Wu / Bowhead whale (Balaena mysticetus), group socialising in shallow water, aerial view. Part of larger group of more than 50 whales congregating, Sea of Okhotsk sub-population, Russia.

Tony Wu / Humphead parrotfish (Bolbometopon muricatum) shoal spawning in early morning, part of mass aggregation of thousands of fish. Caroline Islands, Palau.

Alex Mustard / Southern stingray (Dasyatis americana) two swimming over sand bar, under stormy sky. Grand Cayman, Cayman Islands. British West Indies.

Sergio Hanquet / Loggerhead turtle (Caretta caretta) tangled in fishing net. Tenerife, Canary Islands. 2019.

Alex Mustard / Yellow tube sponge (Aplysina fistularis) on coral reef, diver exploring in background. Black Rock Drop Off, East End, Grand Cayman, Cayman Islands, British West Indies. Model released.

Alex Mustard / Dugong (Dugong dugon) male and juvenile Golden trevally (Gnathanodon speciosus) swimming over Seagrass (Halophila stipulacea) meadow. Marsa Nabaa, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) feeding on Seagrass (Halophila stipulacea), blowing sand out of nostrils, on sea floor. Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Green turtle (Chelonia mydas) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

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.

Shane Gross / Flying fish (Exocoetidae) in Sargasso Sea, Atlantic Ocean.

Guy Edwardes / Milky Way above Durdle Door rock arch. Jurasic Coast, Dorset, England, UK. August 2019. Composite image.

Guy Edwardes / Aurora borealis above sea stacks, Reykjanes Peninsula, Iceland. 2019.

David Tipling / Grey seal (Halichoerus grypus) female in surf, Horsey, Norfolk, England, UK, February.

David Tipling / Grey seal (Halichoerus grypus) pup, Horsey, Norfolk, England, UK, February.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female with suckling calf. Vava'u Islands, Tonga.

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

Tony Wu / Sperm whale (Physeter macrocephalus), ten swimming together in gathering of more than 50 individuals. Whales with flatulence and defecating. Sri Lanka.

Shane Gross / Caribbean reef shark (Carcharhinus perezi), two from below, one close up. Caribbean Sea off Gardens of the Queen National Park, Cuba.

Shane Gross / American crocodile (Crocodylus acutus) with open mouth amongst Seagrass (Alismatales). Gardens of the Queen National Park, Cuba.

Gary Bell/ Oceanwide / Leopard Flounder (Bothus pantherinus) camouflaged on ocean floor, Anilao, Philippines

Doug Gimesy / Little blue penguin (Eudyptula minor), two standing on rocks at night, silhouetted against Melbourne city lights. St Kilda breakwater, Victoria, Australia. December 2016.

Theo Bosboom / Rocks and sea stacks in the surf at Playa del Silencio in Asturias on the Northwest coast of Spain. May 2015

Doug Gimesy / Little penguin (Eudyptula minor) on rocks of St Kilda breakwater, Melbourne city lights in background. Victoria, Australia. January 2017.

Theo Bosboom / Aerial of patterns of receding waves, Playa del Silencio, Asturias, Spain. April 2018

Theo Bosboom / Crashing waves at large basalt wall, Arnarstapi, Snaefellsnes, Iceland. May 2013

Theo Bosboom / Common limpets (Patella vulgata) hit by a big wave from the Atlantic ocean at the coast of Crohy head, Donegal, Ireland. November 2017

Theo Bosboom / Sea stacks consisting of flysch rock battered by the incoming tide, playa de Gueirua, Asturias, Northwest Spain. October 2015

Theo Bosboom / Winter landscape at Luskentyre beach, Isle of Lewis, Scotland, North Harris in the background. February 2018.

Theo Bosboom / Powerful waves rolling in at the Atlantic coast of Iceland near Dyrholey during a powerful winter storm. February 2016

Theo Bosboom / Sun rays through stormy clouds, and snow covered beach, Varanger Peninsula, Norway. March.

Theo Bosboom / Wave breaking in front of the two famous sea stacks Risin and Kellingin on the Faroe Islands. March 2018.

Theo Bosboom / Sand patterns at sunrise, Praia da Adraga, Sintra, Portugal. December 2016

Theo Bosboom / Blue hour before sunrise at the dunes of Seilebost beach, Lewis and Harris, Scotland. February 2018.

Theo Bosboom / Patterns on Carrickfinn beach with sand and water mixed with tannin dyed water from peat stream. Donegal, Ireland, November.

Theo Bosboom / Winter sunsrise at Seilebost beach, Isle of Harris, Scotland. February 2018

Theo Bosboom / Patterns of algae on a limestone rock with sand, White sands beach, Causeway coast, Northern Ireland. April 2016.

Theo Bosboom / Star shaped sand pattern as photographed at low tide at Luskentyre beach, Lewis and Harris, Scotland, UK, October.

Theo Bosboom / Sand patterns created by receding waves, Quiberon, Brittany, France. August 2017

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.

Jordi Chias / Chinstrap penguin (Pygoscelis antarcticus) carcass after leopard seal attack, Antarctic Peninsula, Antarctica.

Jordi Chias / Humped rockcod (Gobionotothen gibberiformis), Antarctic Peninsula, Antarctica.

Jordi Chias / Wandering albatross (Diomedea exulans) flying on the open ocean, Drake passage, Antarctic Peninsula, Antarctica.

Jordi Chias / Black rockcod (Notothenia coriiceps), Antarctic Peninsula, Antarctica.

Jordi Chias / Jellyfish (Diplulmaris antarctica) Cuverville, Antarctic Peninsula, Antarctica.

Jordi Chias / Jellyfish (Diplulmaris antarctica) Cuverville, Antarctic Peninsula, Antarctica.

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

Jordi Chias / Crocodile icefish or White-blooded fish (Channichthyidae), Antarctic Peninsula, Antarctica.

Jordi Chias / Crabeater seals (Lobodon carcinophaga) resting on ice floating ice sheet, Antarctic Peninsula, Antarctica.

Ismaele Tortella / Pod of Killer whales (Orcinus orca) at the surface, northern Norway, November.

Ismaele Tortella / Pod of Killer whales (Orcinus orca) at the surface, northern Norway, November.

Ismaele Tortella / Pod of Killer whales (Orcinus orca) spyhopping, northern Norway, January 2019

Ismaele Tortella / Pod of Killer whales (Orcinus orca) surfacing, northern Norway, January 2019

Ismaele Tortella / Winter landscape of Sommaroy island, close to Tromso, Norway, February 2019.

Ismaele Tortella / Aerial shot of two Humback whales (Megaptera novaeangliae) surfacing, northern Norway, November.

Ismaele Tortella / Aerial shot of two Humback whales (Megaptera novaeangliae) diving, northern Norway, November.

Pascal Kobeh / Parrotfish (Scarus / Chlorurus sp.) sleeping at night, New Caledonia, Pacific Ocean.

Peter Lewis / Starling (Sturnus vulgaris) murmuration at sunset, West Pier, Brighton, England, UK.

Pascal Kobeh / White tip shark (Triaenodon obesus) laying on the sandy bottom, New Caledonia, Pacific Ocean.

Pascal Kobeh / Hard coral (Porites lutea) with Christmas-tree worms (Spirobranchus giganteus), New Caledonia, Pacific Ocean.

Pascal Kobeh / Cup coral (Turbinaria mesenterina) housing Blackblotch or blackspot squirrelfish (Sargocentron melanospilos) and a longfin bannerfish (Heniochus acuminatus), New Caledonia, Pacific Ocean.

Pascal Kobeh / Limestone formations are reflected on the surface in Luengoni fresh water cave, Lifou with a diver in the background, New Caledonia, Pacific Ocean.

Pascal Kobeh / Pair of courting Egg-eating / Turtleheaded sea snakes (Emydocephalus annulatus) New Caledonia, Pacific Ocean.

Pascal Kobeh / Pair of courting Egg-eating / Turtleheaded sea snakes (Emydocephalus annulatus) New Caledonia, Pacific Ocean.

Pascal Kobeh / Pair of courting Egg-eating / Turtleheaded sea snakes (Emydocephalus annulatus) New Caledonia, Pacific Ocean.

Pascal Kobeh / Pair of courting Egg-eating sea snakes / Turtleheaded sea snakes (Emydocephalus annulatus) New Caledonia, Pacific Ocean.

Pascal Kobeh / Zebra / Leopard shark (Stegostoma varium) swimming away from the bottom, New Caledonia, Pacific Ocean.

Pascal Kobeh / Zebra / Leopard shark (Stegostoma varium) swimming away from the bottom, New Caledonia, Pacific Ocean.

Pascal Kobeh / Close-up of a Egg-eating / Turtleheaded sea snake (Emydocephalus annulatus) with eggs coming out of its mouth, New Caledonia, Pacific Ocean.

Pascal Kobeh / Three Pygmy seahorses (Hippocampus bargibanti) on a Seafan / Gorgonian (Muricella sp) including one or several pregnant males. New Caledonia, Pacific Ocean

Pascal Kobeh / Four Pygmy seahorses (Hippocampus bargibanti) on a Seafan / Gorgonian (Muricella sp. ) including one or several pregnant males. New Caledonia, Pacific Ocean.

Pascal Kobeh / Graysby seabass (Cephalopholis cruentata) on the reef, Yucatan peninsula, Mexico, Caribbean.

Pascal Kobeh / School of white margates or white grunts (Haemulon album) Yucatan peninsula, Mexico.

Pascal Kobeh / Close-up of a school of bluestriped or boar grunts (Haemulon sciurus) Yucatan peninsula, Mexico, Caribbean.

Pascal Kobeh / Goldentail moray (Gymnothorax miliaris) Cozumel Island, Yucatan peninsula, Mexico.

Pascal Kobeh / Queen angelfish or blue or golden angelfish (Holacanthus ciliaris) Cozumel Island, Yucatan peninsula, Mexico.

Pascal Kobeh / Group of Grey seals (Halichoerus grypus grypus) resting on a rock around Bonaventure Island, Gulf of Saint Lawrence, Canada