Pete Oxford / Yellow-tailed Surgeonfish (Prionurus laticlavius) school and snorkeler, Galapagos Islands, Ecuador

Pete Oxford / Yellow-tailed Surgeonfish (Prionurus laticlavius) school and snorkelers, Galapagos Islands, Ecuador

Pete Oxford / Pacific Green Sea Turtle (Chelonia mydas agassizi) and snorkeler, Galapagos Islands, Ecuador

Franco Banfi / Free diver with Blue shark (Prionace glauca) Pico Island, Azores, Portugal, Atlantic Ocean, July. No release available.

Michele Westmorland / Snorkeler swimming with harmless Jellyfish (Mastigias papua etpisonii), Jellyfish Lake, Rock Islands, Palau, Micronesia.

Doug Perrine / Researcher Guy Stevens photographs belly spot identification pattern of Reef manta ray (Manta alfredi formerly Manta birostris) feeding on plankton, Hanifaru Bay, Baa Atoll, Maldives, Indian Ocean, Oc...

Juergen Freund / Flat calm seas of Tubbataha Reef, with a snorkeler swimming at the surface. Tubbataha National Marine Park, Philippines, April 2009.

Juergen Freund / Split level of snorkeler over coral reef on white sandy seabed contrasting with dry topside landscape in background, Komodo NP, Indonesia, August 2009. Model released.

Juergen Freund / Snorkeler swimming through a school of Oxeye scads (Selar boops) in the house reef of Miniloc Island Resort, El Nido island, Palawan, Philippines, May 2009. Model released.

Juergen Freund / Snorkeler swims amongst Sergeant major damselfish (Abudefduf vaigiensis) at the house reef of Miniloc Island Resort, El Nido Island, Palawan, Philippines, May 2009. These fish gather in a dense mass w...

Juergen Freund / Snorkeler swimming underwater, split level, with Miniloc Island Resort in the background, El Nido, Palawan, Philippines, May 2009. Model released

Alex Mustard / Caribbean reef shark (Carcharhinus perezi) swimming over a coral reef, beneath a snorkeler and boat. Near Grand Bahama, Bahamas. Tropical West Atlantic Ocean.