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.

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 / Whitetip reef shark (Triaenodon obesus) resting on sea floor. Kauai, Hawaii.

Alex Mustard / Hedgehog seahorse (Hippocampus spinosissimus) female moves over a sandy seabed. Dauin, Negros Island, Philippines. Bohol Sea, tropical west Pacific Ocean.

Alex Mustard / Diver (Predrag Vuckovic) is dwarfed by Great hammerhead shark (Sphyrna mokarran). This species can reach over 6m in length. South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, We...

Franco Banfi / Green moray (Gymnothorax funebris) Santa Lucia, Camaguey, Cuba, Caribbean Sea, Atlantic Ocean

Franco Banfi / Corals attached to structure of bio-rock, a method of enhancing the growth of corals and aquatic organisms, Karang Lestari Pemuteran project, Desa Pemuteran, Bali Island, Indonesia, Pacific Ocean.

Franco Banfi / Tiger shark (Galeocerdo cuvier) Northern Bahamas, Caribbean Sea, Atlantic Ocean.

Franco Banfi / Scuba diver and Tiger shark (Galeocerdo cuvier) Northern Bahamas, Caribbean Sea, Atlantic Ocean. March 2009.

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.