Giant Freshwater StingrayThis gallery is part of a special news series on global water issues.The giant freshwater Mekong River stingray is just one of many megafish species that could be threatened by ambitious dam-building plans in the Mekong River Basin.(Read the full story.)The outcome of a meeting last week among four Southeast Asian countries could determine whether construction of the first of 11 controversial dams on the Mekong River can proceed. The dams are designed to generate electricity for the region, but environmentalists fear they will disrupt the Mekong's delicate freshwater ecology, which supports dozens of other critical species, and that they will threaten local communities who rely on the river for food and jobs.

This giant fish, found near the Cambodia-Vietnam border in 2002 by National Geographic Emerging Explorer Zeb Hogan, measured 162 inches (413 centimeters) from nose to tail.

(Read more in “GIANT STINGRAY PICTURE: Largest Freshwater Fish?” and watch video of this enormous species.)

—Tasha Eichenseher and Ker Than

Photograph by Zeb Hogan, AP