Fish hearing specialists (e.g. goldfish, holocentrids, moromyrids) are known to evolve specialised structures, e.g. Weberian ossicles; gas-filled bullae, swimbladder diverticulae to enhance their hearing abilities. The anabantoid fish have gas-filled suprabranchial chambers (SBC) situated in close proximity to inner ears. It is hypothesized that the gas bubbles inside the SBC can modulate hearing abilities of anabantoides. Three sound producing gouramis (blue gouramis Trichogaster trichopterus; kissing gouramis Helostoma temminckii; dwarf gouramis Colisa lalia) were used to test the hypothesis. The baseline audiograms (tested at 300, 500, 800, 1500, 2500, 4000 Hz) were obtained by the auditory brainstem response (ABR) protocol. The air bubbles inside the SBC were then driven out by water currents and the audiograms were measured again. Significant changes (i.e., thresholds) of audiograms were observed in all three species. The results support the hypothesis that air bubbles inside the SBC can affect hearing abilities of gouramis. However, the absence of air bubbles inside the SBC did not reduce hearing frequency ranges which indicated that swimbladder might also play a role in modulating hearing abilities of gouramis. The best hearing frequency of each species matched with the dominate frequency of the sound produced. This is an indication of co-evolution of sound production and hearing ability in anabantoids.
Stories from receivers' end - How do suqrabranchial chambers modulate hearing abilities of sound producing anabantoid fishes? [abstract]
(1998).
Stories from receivers' end - How do suqrabranchial chambers modulate hearing abilities of sound producing anabantoid fishes? [abstract]. Bioacoustics,
Volume 9
(2):
159
Abstract: