Male gobies of the genus Bathygobius are coniferous during courtship. The mechanism by which the sounds are produced is, however, unknown. Early studies on sound production by males of B. soparator suggested that these sounds are hydrodynamic in nature, being produced by the forcible ejection of water through the gill opening. The mechanism of sound production by the closely related species B. curacao was investigated and three lines of evidence are presented which support the hydrodynamic hypothesis. First, similarities between the sounds produced by courting males and by ejecting water through a pipette demonstrated that hydrodynamic forces nark readily produce such sounds. Second, the behavioural motor patterns occurring during sound production are consistent with the hypothesis that water is being ejected through the gill openings. Finally, morphological examination revealed an apparent lack of specialized features associated with sound production, effectively eliminating stridulating and swim bladder mechanisms. These results represent the strongest evidence to date in support of any proposed mechanism of sound production in tile gobiids.
Bathygobius curacao, sound production, hydrodynamic.