Claudio Contreras / Green turtle (Chelonia mydas) Akumal, Caribbean Sea, Mexico, January. Endangered species.

Claudio Contreras / Green turtle (Chelonia mydas) over sea floor, Akumal, Caribbean Sea, Mexico, January. Endangered species.

Claudio Contreras / Green turtle (Chelonia mydas) wide angle view of fin, Akumal, Caribbean Sea, Mexico, January. Endangered species.

Alex Mustard / Hairy pipehorse (Acentronura dendritica) female swimming over the seabed with her prehensile tail in the air. Bloody Bay Wall, Little Cayman, Cayman Islands. Caribbean Sea.

Alex Mustard / Galapagos sea lions (Zalophus wollebaeki) young playing in shallow water. Floreana Island, Galapagos Islands, Ecuador. East Pacific Ocean

Alex Mustard / Group of predators hunting together, in an example of 'Nuclear foraging'. The Moray eel (Gymnothorax javanicus) flushes out prey, and is followed by a Napolean wrasse (Cheilinus undulatus) and a Bluef...

Alex Mustard / Reef octopus (Octopus cyanea) portrait near wreck. Gubal Island, Egypt. Red Sea.

Alex Mustard / Tasseled wobbegong shark (Eucrossorhinus dasypogon) yawning. Citrus Ridge, Yanggefo Island, Gam Island, Raja Ampat, West Papua, Indonesia.

Doug Perrine / Barjacks (Caranx ruber), Yellowtail snapper (Ocyurus chrysurus), and Sergeant major damselfish (Abudefduf saxatilis) swimming around wreck of bow gun on C-58 shipwreck off Puerto Morelos, near Cancun,...

Georgette Douwma / Erect rope sponge (Amphimedon compressa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Stove-pipe sponge (Aplysina archeri) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.

Georgette Douwma / Erect rope sponge (Amphimedon compressa) Bonaire, Netherlands Antilles, Caribbean, Atlantic Ocean.