Field studies of hearing in teleost fish
- C. J. Chapman1
© Biologischen Anstalt Helgoland 1973
1. Field measurements of hearing in haddock,Melanogrammus aeglefinus, pollack,Pollachius pollachius and ling,Molva molva, show that they are sensitive to sounds in the frequency range from 30 to 500 Hz, with greatest sensitivity from 100 to 300 Hz.
2. At the most sensitive frequencies the thresholds varied between — 15 to — 25 dB relative to a sound pressure of 1µbar.
3. In all three species, the thresholds at some frequencies were affected by the level of ambient sea noise. A direct correlation between the thresholds and the spectrum level of sea noise was obtained in haddock and pollack.
4. The masking effect of sea noise was confirmed in some experiments on cod,Gadus morbua and haddock, where the background noise level was raised artificially. It was found that the masking of a tone signal was reduced by about 8 dB when the tone and noise were from different directions (85° apart), suggesting that directional discrimination may be well developed in these fish.