Among the fish populations that could be harmed by the Xayaburi dam in Laos is the critically endangered Mekong giant catfish, considered by the Guinness Book of World Records to be the world’s largest freshwater fish. The fish, which grows to 650 pounds and about 10 feet long, is only found in the Mekong River. It is migratory, moving between downstream habitats in Cambodia upstream to northern Thailand and Laos each year to spawn. Some experts fear the Xayaburi dam could block the migration and drive the giant catfish to extinction. (Photo by Courtesy of Zeb Hogan/University of Nevada, Reno)

Gerald Herbert is a staff photographer for the AP based in New Orleans, Louisiana. Before that he was a staff photographer for the Washington Times, the New York Daily News and a freelancer for the AP in New Orleans, Boston and New York. Photo: A worker grooms away tracks after an alligator crossed through a sand trap on the 14th hole during the first round of the PGA Tour Zurich Classic golf tournament at TPC Louisiana in Avondale, La., Thursday, April 25, 2013. (Photo by Gerald Herbert/AP Photo)

A view of an installation as part of the “S.A.C.R.E.D” exhibition by Chinese artist Ai Weiwei during the 55th La Biennale of Venice, in the church of Sant'Antonin in Venice May 28, 2013. (Photo by Stefano Rellandini/Reuters)

A comedic photo of a cheetah appearing to find something hilarious by Dutton Robert for the Comedy Wildlife Photo Awards 2016, South Africa, April, 2012. (Photo by Dutton Robert/Barcroft Images/Comedy Wildlife Photo Awards)

Local residents crowd a swimming pool during a hot weather in Suining, Sichuan province, 27 July 2008. (Photo by Reuters/Stringer)

In this Friday, September 15, 2017 photo, ballet dancers from Uruguay’s National ballet of the Sodre put on lipstick before a dress rehearsal for Romeo and Juliet in Montevideo, Uruguay. Dancers practice Monday through Friday for eight hours at a time. (Photo by Matilde Campodonico/AP Photo)