Greg Lecoeur's image of the migration of the sardines along the wild coast of South Africa took grand prize in the National Geographic Nature Photographer of the Year Contest.

Black tip sharks are seen swimming in a lagoon near Moorea, French Polynesia.

Lecoeur focuses his work on environmental issues, including illegal hunting and habitat depletion of American crocodiles. He captured this crocodile off the coast of Havana, Cuba. "Mangrove conservation is vital for survival of crocodiles and the good health of the ocean," says Lecoeur.

This scene was captured the same year as Lecoeur's winning photo. "After many hours on the water looking for action, we found a small bait ball hunting near a cape fur seal. It was very artistic to see the seal going through the sardines."

While scuba diving in Spain's Canary Islands, Lecoeur encountered green turtles. "It was early morning and the sunbeam pierced the [surface of the water]. I adjusted the setting of my camera and I waited for the turtles to come close enough to trigger my camera. After a little while, the turtles were circling around us and it was a great opportunity to photograph them."