David Fleetham / Blacktip reef shark (Carcharhinus melanopterus) swimming just below surface at sunset, split level view. Off the island of Yap, Micronesia.

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

Ralph Pace / Galapagos Shark (Carcharhinus galapagensis), Reviliagigedo Island, Mexico

Ralph Pace / Silky Shark (Carcharhinus falciformis), Galapagos Shark (Carcharhinus galapagensis), Dusky Shark (Carcharhinus obscurus), and Black-tip Shark (Carcharhinus limbatus) group working with Yellowfin Tuna...

Ralph Pace / Silky Shark (Carcharhinus falciformis), Galapagos Shark (Carcharhinus galapagensis), Dusky Shark (Carcharhinus obscurus), and Black-tip Shark (Carcharhinus limbatus) group working with Yellowfin Tuna...

Claudio Contreras / Black grouper (Mycteroperca bonaci) and Caribbean Reef Shark (Carcharhinus perezi), Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba, January

Claudio Contreras / Silky shark (Carcharhinus falciformis) two swimming together, Jardines de la Reina / Gardens of the Queen National Park, Caribbean Sea, Ciego de Avila, Cuba, January. Vulnerable species.

Alex Mustard / Whitetip shark (Carcharhinus longimanus) head on beneath the surface. Rocky Island, Egypt. Red Sea

Jordi Chias / Split level view of Blue shark (Prionace glauca) at surface at sunset, Azores Islands, Portugal, Atlantic 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.

Franco Banfi / Lemon shark (Negaprion brevirostris) Northern Bahamas, Caribbean Sea, Atlantic Ocean