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) resting on sea floor and two juvenile Golden trevally (Gnathanodon speciosus). Marsa El Shouna, Marsa Alam, Egypt.

Alex Mustard / Whale shark (Rhincodon typus) close to the camera with a golden trevally fish (Gnathanodon speciosus) and outline of another whale shark behind , in the plankton-rich green waters of La Paz bay, Baja...

Shane Gross / Almaco jack (Seriola rivoliana) uses a discarded fishing net, drifting in the open ocean as shelter. The Bahamas.

Nick Hawkins / Blue shark (Prionace glauca) with a pair of pilot fish (Naucrates ductor) off Halifax, Nova Scotia, Canada. July.

David Fleetham / California yellowtail (Seriola lalandi dorsalis) Guadalupe Island, Mexico.

Jordi Chias / Blue spotted trevally (Caranx bucculentus) hunting small fish in the reef, South Ari Atoll, Maldives, Indian Ocean.

Jordi Chias / European barracuda (Sphyraena sphyraena) and Bluefish (Pomatomus saltatrix) circling baitball of Atlantic horse mackerel (Trachurus trachurus) Formigas Islets, Azores. Finalist in the Underwater Categ...

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) female at night with Bar jacks (Caranx ruber), South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream, West Atlantic Ocean.

Alex Mustard / Great hammerhead shark (Sphyrna mokarran) swimming over a sandy seabed, accompanied by Rainbow runners (Elagatis bipinnulata) South Bimini, Bahamas. The Bahamas National Shark Sanctuary. Gulf Stream,...

Jordi Chias / Mobula / Chilean devil ray (Mobula tarapacana) with remora (Remora brachyptera) and Amberjacks (Serila dumerilli) Santa Maria Island, Azores, Atlantic Ocean

Pete Oxford / Whale Shark (Rhincodon typus) close up of spotted skin, with Golden trevally (Gnathanodon speciosus) Cenderawasih Bay, West Papua, Indonesia.