swim bladder swim bladdera gas filled organ that is primarily used for buoyancy control but is also important for hearing in some fishes. Related Articles: Glossary: drummingGlossary: Weberian ossiclesHot Topic- Passive Acoustic Monitoring Critical to Vaquita Conservation EffortsHow is sound used to locate fish?DOSITS VideosBlast Injury, Barotrauma, and Acoustic TraumaHow do fish produce sounds?What components of sound are used for hearing?How is sound used to identify fish?Fish Finding Sonar Chris Knowlton2017-02-26T20:10:03-05:00