Startle Response in Herring: The Effect of Sound Stimulus Frequency, Size of Fish and Selective Interference with the Acoustico-Lateralis System
diaphragm, herring, low frequencies, membrane, sound, startle response, tank
Journal or Book Title
Journal of the Marine Biological Association of the United Kingdom
Herring (Clupea harengus L.) show a characteristic 'startle' response when subjected to vibrational stimuli from a diaphragm in the wall of their tank. Threshold measurements on fish from 2.8 to 17 cm total length tested at frequencies from 70 to 200 Hz showed that the response was elicited by sound pressures between 2 and 18 Pa, the most sensitive fish being in the length range from 8-11 cm. Intermediate-sized fish of 12-13 cm also responded to sounds from a loudspeaker in the air above the tank, the mean threshold being about 5 Pa. The stimulus was thought to be the sound pressure rather than the particle velocity component of the stimulus, the gas-filled pro-otic bulla acting as part of the pressure detecting system. Pre-treatment of fish by shock pressure increases of 4 atm to burst the bulla membrane increased the threshold about ten times. The bulla membrane is coupled hydrodynamically with the head line lateral system via a lateral recess membrane. Decoupling of this link by cutting a window over the lateral recess did not affect the response much, not did treatment of the lateral line by methylene blue or streptomycin as blocking agents.