First use of acoustic calls to distinguish cryptic fish species: Dascyllus aruanus complex as a case study

From a practical point of view, the determination of species in the wild is based on their phenotypes. Consequently, many species remain unknown because they are visually indistinguishable from described species. Although molecular methods and advances in bioacoustical analysis have been extensively used to uncover cryptic species, the combination of both methodologies is still rare and concerns only some terrestrial taxa such as insects, bats, frogs and birds. In this study, we aim to determine whether the sounds produced by different populations of fish can also be a tool to distinguish and identify cryptic species. The humbug damselfish complex, Dascyllus aruanus, is widely distributed across the Indo-Pacific Ocean and, since 2019, is thought to be composed of at least two species with Dascyllus aruanus in the Pacific Ocean and Dascyllus abudafur in the Indian Ocean. Recordings were made over a large geographical area with populations from Madagascar (Indian Ocean), Taiwan (Pacific O...