Organized by the London-based Chartered Institution of Water and Environmental Management, the Environmental Photographer of the Year contest honors amateur and professional photographers who "raise awareness of environmental and social issues." This year's edition drew more than 4,500 entries from photographers in 97 countries.

—John Roach

German photographer Florian Schulz said the scope of the ray congregations was unknown until he and a pilot happened upon the gathering while searching for migrating whales.

Perhaps just as rare is the composition Schulz captured. "I was able to show how these rays are jumping out of the water," he said, "and at the same time I'm able to show—almost like an underwater photograph—how there're layers and layers and layers of rays."

A gray seal pokes its head through "clouds" of plant life in a winning picture by Estonian photographer Kaido Haagen.

Based in the capital city, Tallinn (map), Haagen didn't have to travel too far for the otherworldly image, which was captured about six feet (two meters) under the Baltic Sea near the Estonian island of Vilsandi (map).

Laid by April each year, European common frog tadpoles cluster in clumps of eggs on the bottom of a spring-fed Hungarian mountain lake in a picture by underwater photographer Bela Nasfay.