Audiograms of walking catfish at the indicated frequencies. The suprabranchial chamber (SC) (A) or bladder (WGB) was deflated (B) and then allowed to replenish with gas. Audiograms were determined before (baseline) and after (deflated) surgery and after recovery (recovery). Data are shown as means ± SE. Asterisk (*) indicates p < 0.05; double asterisks (**) indicate p < 0.01.