New Study Explores Relationship Between Swim Bladder and Hearing

Biologists from the University of Vienna investigated morphological differences in the swim bladders of cichlid fishes and the relationship between swim bladder shape and function.  Their results were recently published in the journal PLoS ONE.

The swim bladder’s primary function in bony fish is buoyancy, but in some species it also aids in sound production and can actually improve hearing.

Cichlid. Photo credit Nicolas Couthouis.

University of Vienna’s behavioral scientist and bioacoustician Tanja Schulz-Mirbach explains, “These fish are perfect for such an investigation because this fish family possesses a large variety of swim bladders ranging from tiny reduced ones to large highly specialized swim bladders with extensions up to the inner ear.”

There are over 1,300 species of cichlid fishes, ranging in habitats from the ocean floor to fast-flowing river basins.  All of these species have swim bladders that reflect their particular habitat.  For example, some cichlids living in calm waters have large swim bladders that are not connected to the inner ear.

They found that “species having specialized swim bladders detect higher sound frequencies and lower sound levels than species having reduced swim bladders,” explains Schulz-Mirbach.

You can read the full press release here: Cichlid fish: How does the swim bladder affect hearing?

And you can read more of their results published in PLos ONE here: Relationship Between Swim Bladder Morphology and Hearing Abilities–A Case Study on Asian and African Cichlids.

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