Chapter 2 - Fish Sound Production: Insights

In addition to briefly reviewing sound-producing mechanisms, this chapter
focuses on an under-appreciated evolutionary process, exaptation, which could aid in
understanding the independent origins and high diversity of sound-producing mechanisms
in fishes. Existing anatomical structures first used in non-voluntary sound production
provide advantages that result in further selection and refinement of
sophisticated sonic organs. Moreover, comparisons of the relationships between fish
size and spectral features in multiple not phylogenetically related species highlight
two acoustic patterns. In species using superfast muscles, the slope of the relationship
between fish size and sound frequency is weak (1°–5°) so that emitter size is unlikely
inferred from call frequency. In other species that stridulate or use bones or tendons to
stimulate the swimbladder, the high slopes (25°–80°) indicate major differences in the
call frequencies within a species. These signals likely convey important information
(size and potential fitness of the emitter) to conspecific receivers.