Harmonics in courtship sounds of four Caribbean reef fish species of the genus Eupomacentrus (Pomacentridae)

Four species of sympatric damselfishes (Eupomacentrus, Pomacentridae) produce and apparently use sounds in their courtship behaviour. Up to now, time structure elements were considered the key parameters in species recognition. Audible differences between the species, that can be ascribed to frequency characteristics of these sounds, are described here for the first time. It was found that both classes of parameters, i.e. of time structure and of frequency, can equally be responsible for species specificity within one locality. In other localities, different parameters (e.g. optical signals) or different combinations of different modalities could lead to the same result