Structures for the detection of acoustic stimuli in the Atlantic codfish, Gadus morhua

Abstract

Codfish, Gadus morhua, were classically conditioned to respond to tonal stimuli with a change in hear rate. Thresholds were obtained at frequencies from 10 to 600 Hz. Sensitivity of receptors was determined by ablation operations. The sacculus had the lowest threshold at 150 Hz (−35 dB re 1 μbar) and the lagena and utriculus might have successively higher thresholds. One fish was about 9 dB less sensitive at 150 Hz after swim‐bladder ablation. A piezoelectric transduction mechanism was hypothesized for the sacculus. The lateral line might detect the acoustic stimulus and be most sensitive at 75 Hz to particle velocity (−14 dB re 1 μvar).