Fish ears are sensitive to sex change.

Many reef fishes change sex during their life. The testing of life-history theory and effective fisheries management therefore relies on our ability to detect when this fundamental transition occurs. This study experimentally illustrates the potential to glean such information from the otolithic bodies of the inner-ear apparatus in the sex-changing fish Parapercis cylindrica. It will now be possible to reconstruct the complete, often complex life history of hermaphroditic individuals from hatching through to terminal reproductive status. The validation of sex-change associated otolith growth also illustrates the potential for sex-specific sensory displacement. It is possible that sex-changing fishes alter otolith composition, and thus sensory-range specificity, to optimize life history in accordance with their new reproductive mode.