For many years Professor Eric Parmentier – who directs the Functional and Evolutionary Morphology Laboratory of the University of Liege - has been tracking sounds emitted by fishes in order to better understand the way they live. A recent study, unique in the world, has made it possible to compare the huge amount of sounds emitted by different fish communities at a depth of 120 meters. This research has been the subject of a publication in the prestigious American magazine PNAS (Proceedings of the National Academy of Sciences).