Complex sentence: The swim bladder of species in "Sciaenidae", which is used as a resonating chamber is more expansive and branched than species outside of "Sciaenidae", this larger swim bladder aids in croaking.
Split into simpler sentences: The swim bladder of species in "Sciaenidae", is used as a resonating chamber. The large swim bladder is more expansive and branched than species outside of "Sciaenidae", which aids in croaking.