Underwater sounds of the haddock,Melanogrammus aeglefinus

Abstract
It has not been known with certainty that the haddock produces underwater sounds of biological significance, though various authors have suggested the possibility.Descriptions are given of sounds (grunts and rasp-like noises) produced in particular behavioural contexts by haddock maintained in tanks, and of sounds recorded at sea and attributed to haddock. Oscillograms and a spectrogram of these sounds are given. It is suggested that the sounds are involved in aggression and self-defence.The sound-producing mechanism is described.