title: Assessing acoustic communication active space in the Lusitanian toadfish.
abstract: The active space of a signal is an important concept in acoustic communication as it has implications for the function and evolution of acoustic signals. However, it remains mostly unknown for fish as it has been measured in only a restricted number of species. We combined physiological and sound propagation approaches to estimate the communication range of the Lusitanian toadfish's ( ITALIC! Halobatrachus didactylus) advertisement sound, the boatwhistle (BW). We recorded BWs at different distances from vocalizing fish in a natural nesting site at ca. 2-3 m depth. We measured the representation of these increasingly attenuated BWs in the auditory pathway through the auditory evoked potential (AEP) technique. These measurements point to a communication range of between 6 and 13 m, depending on the spectral characteristics of the BW. A similar communication range (ca. 8 m) was derived from comparing sound attenuation at selected frequencies with auditory sensitivity. This is one of the few studies to combine auditory measurements with sound propagation to estimate the active space of acoustic signals in fish. We emphasize the need in future studies for estimates of active space to take informational masking into account.
authors.affiliation: Departamento de Biologia Animal and cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisbon 1749-016, Portugal dbalves@fc.ul.pt.
authors.forename: Daniel
authors.initials: D
authors.lastname: Alves
authors.affiliation: MARE - Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Lisbon 1149-041, Portugal.
authors.forename: M Clara P
authors.initials: MC
authors.lastname: Amorim
authors.affiliation: Departamento de Biologia Animal and cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisbon 1749-016, Portugal.
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Fonseca
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D024541:Batrachoidiformes / Q000502:physiology*; D017753:Ecosystem; D005072:Evoked Potentials, Auditory; D013016:Sound; D013018:Sound Spectrography; D014828:Vocalization, Animal / Q000502:physiology*
keywords: AEP technique; Auditory evoked potential; Boatwhistle; Communication range; Fish; Information masking