In this photo released by World Wildlife Fund-National Geographic, two Thai fishermen show a 293-kilogram (646-pound) giant catfish they caught from the Mekong River in Chiang Khong district of Chiang Rai province, northern Thailand in mid-May, 2005. Six proposed dams on the Mekong River could displace up to 75,000 villagers and harm hundreds of species like the endangered giant catfish, conservationists warned Tuesday, Nov. 13, 2007. [Agencies]