PlanetCatfish.com

LIMA—Once upon a time, thousands of dorados, a giant among catfish, would swim more than 3000 kilometers from the mouth of the Amazon River to spawn during the austral autumn in Bolivia's Mamoré River, in the foothills of the Andes. But the dorado, which can grow to more than 2 meters in length, is disappearing from those waters, and scientists blame two hydropower dams that Brazil erected a decade ago on the Madeira River.