Data from: Wall structure and material properties cause viscous damping of swimbladder sounds in the oyster toadfish Opsanus tau

Despite rapid damping, fish swimbladders have been modelled as underwater
resonant bubbles. Recent data suggest that swimbladders of sound-producing
fishes use a forced rather than a resonant response to produce sound. The
reason for this discrepancy has not been formally addressed, and we
demonstrate, for the first time, that the structure of the swimbladder
wall will affect vibratory behaviour. Using the oyster toadfish Opsanus
tau, we find regional differences in bladder thickness, directionality of
collagen layers (anisotropic bladder wall structure), material properties
that differ between circular and longitudinal directions (stress, strain
and Young's modulus), high water content (80%) of the bladder wall
and a 300-fold increase in the modulus of dried tissue. Therefore, the
swimbladder wall is a viscoelastic structure that serves to damp
vibrations and impart directionality, preventing the expression of
resonance.