MECHANICS OF THE CLUPEID ACOUSTICO-LATERALIS SYSTEM - FREQUENCY RESPONSES

The mechanical responses of several structures in the auditory and lateral-line systems of the sprat Sprattus sprattus (L.) and the herring Clupea harengus L. to oscillatory pressure changes have been observed over a range of frequencies from 0-014 t 0 2600 Hz. The pressures required to give constant responses of the bulla membrane, and the lateral recess membrane varied relatively little between 0-014 and 1000 Hz; above 1000 Hz the sensitivity fell quickly as frequency increased. The responses of the bulla membrane agreed reasonably well with values obtained by calculations based on the tension in the bulla membrane and the dimensions of the different parts of the bulla system. The frequency response curve of the lateral recess membrane agreed in general with that of the bulla membrane. The lateral recess membrane was however somewhat less sensitive to very low frequencies. The frequency response of the utricular floor was measured from low frequency up to 1000 Hz and over this range it was very similar to that of the bulla and lateral recess membranes. All these structures have responses to pressurechange that are linear over a very wide range of pressures. © 1979, Marine Biological Association of the United Kingdom. All rights reserved.