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.

Claudio Contreras / Whale shark (Rhincodon typus) feeding view of tail, Isla Mujeres, Caribbean Sea, Mexico, August. Vulnerable species.

Juergen Freund / Bigfin reef squid (Sepioteuthis lessoniana) blurred motion photograph, Kimbe Bay, West New Britain, Papua New Guinea.

Nick Garbutt / Baby Spot-tail Sharks (Carcharhinus sorrah) on sale in fish souk (market) all caught in the Persian Gulf and many bound for markets in Asia. Sharjah, United Arab Emirates. April 2013

Todd Mintz / Narwhal (Monodon monoceros) diving sequence 1/4, Pond Inlet, Nunavut, Baffin Island, Canadian Arctic, June

Ole Jorgen Liodden / Blue Whale (Balaenoptera musculus) tail fluke above water surface. Spitsbergen, Svalbard, August.

Sergey Gorshkov / Sockeye salmon (Oncorhynchus nerka) spawning, Lake Kuril, Kamchatka, Far East Russia, July

Alex Mustard / Two Atlantic spotted dolphins (Stenella frontalis) over a shallow sand bank. On the left is a juvenile which does not have the characteristic spots of the adults. The adult is carrying a piece of weed...

Alex Mustard / Caribbean Reef Shark (Carcharhinus perezi) portrait in blue water above a coral reef. Grand Bahama, Bahamas. March

Juan Carlos Munoz / Albacore / Longfin tuna (Thunnus alalunga) caught fish, tails on ice. Santona, Cantabria, Spain. August 2011.

Ashley Cooper / Commerson's dolphin (Cephalorhynchus commersonii) swimming round a ship off the Falkland Islands. February 2014

Ashley Cooper / Peale's dolphin (Lagenorhynchus australis) bow riding off the front of a boat, Falkland Islands, South Atlantic. February.