Scientific American: Science Sound(E)scapes: Amazon Pink River Dolphins

… And the Amazon river is rising, then, from the runoff from the Andes. There’s a lull in it, so it’s coming up. So what that means is: there’s migratory catfish coming all the way from the mouth of the Amazon—all the way up to this interface with the Andes and where the upper Amazon drops—and then they’re laying their eggs there. …