Bass tones Mr Lindell is the director of the scientific aquaculture programme at the Marine Biological Laboratory (MBL) in Woods Hole, Massachusetts. And for the last few years, he has been training fish. It's a Pavlovian response, he explains. Just as 19th Century scientist Ivan Pavlov conditioned dogs to associate the sound of a bell with the prospect of food, Mr Lindell's black sea bass associate a 280Hz tone emitted from an underwater speaker with food, and respond by gathering in a partitioned "feeding zone".