Can you hear the dinner bell? Response of cyprinid fishes to environmental acoustic cues

Fishes in the superorder Ostariophysi have excellent hearing due to the presence of a synapomorphic hearing specialization called the Weberian apparatus. This structure connects the swim bladder to the inner ear, and increases both sensitivity and upper hearing range. Although numerous experiments have tested the effects of the Weberian apparatus on hearing, few have provided potential evidence for a current adaptive function for the specialization. We conducted a field-based experiment in which a rock shuffling noise and a white noise were played simultaneously from adjacent speakers in a clear, mountain stream in the southern Appalachian Mountains, U.S.A. Our results indicate that species of Cyprinidae, a family within Ostariophysi, were attracted more to rock shuffling noise than to the white noise. This study provides the first evidence that a broadband environmental sound associated with a potential food source is utilized by a potentially large number of species possessing a hearing specialization.