Young squeaker catfish can already talk and listen to their conspecifics

Abstract

Numerous fish species are able to produce sounds and communicate acoustically. Nevertheless, hearing and sound production in fishes is poorly understood and the ontogenetic development of acoustic communication has only been studied in a few species. So far the yellow marbled squeaker catfish Synodontis schoutedeni is the only species that has been shown to be able to communicate acoustically across generations at all postlarval stages of development. In two further fish species the smallest size groups were not yet able to detect sounds of equal conspecifics. Increasing body size in S. schoutedeni correlates with increasing hearing sensitivity for lower frequencies, decreasing hearing sensitivity at higher frequencies, increasing sound pressure level and duration of stridulation sounds, and decreases in stridulation sound dominant frequency. The excellent hearing sensitivities of S. schoutedeni, which are characteristic for Otophysi (fish with a Weberian apparatus), is probably the reason for their ability to communicate acoustically in early stages of development.