Thousands of Munk's devil rays crowd the Sea of Cortez off Mexico's Baja California Sur state (map) in 2009. The aerial image won top honors and the "Underwater World" category in the 2010 Environmental Photographer of the Year awards.
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."
The International Union for Conservation of Nature lists Munk's devil rays as near threatened, due in part to their vulnerability to gill nets—hard-to-see "curtains" of netting.
Given ray gatherings like the one pictured, Schulz said, "you could imagine a single net could take thousands and thousands."
This helps explain why, upon seeing the winning photo, marine ecologist Giuseppe Notarbartolo di Sciara emailed Schulz to express his delight at seeing so many Munk's devil rays thriving in a single frame. Di Sciara helped identify the species in 1987.
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.