Awareness reactions and avoidance responses to sound in juvenile Atlantic salmon, Salmo salar L.

• Published in: Journal of Fish Biology
• Main Authors: Knudsen, F. R., Enger, P. S., Sand, O.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1992.tb02602.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1992.tb02602.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1992.tb02602.x

The possibility of using intense sound as a deterrent for juvenile Atlantic salmon ( Sulmo salar L. ) was studied by recording both physiological awareness reactions in an acoustic tube and behavioural avoidance responses in a pool. The measured awareness reactions consisted of decreased heart rate and breathing movements. Three criteria for the awareness reaction were used to compare the effect of different frequencies between 5 and 150 Hz: (i) threshold for spontaneous awareness reactions relative to the hearing thresholds, (ii) magnitude of the change in heart rate, (iii) degree of habituation to sound. After these criteria the lowest frequencies (5–10 Hz) were most effective in eliciting an awareness reaction from the fish. The responses of freely swimming fish to 10 and 150 Hz sounds were studied in an artificial pool. Juvenile salmon showed avoidance responses to 10 Hz stimulation at intensities 10–15 dB above the threshold for spontaneous awareness reactions measured in the acoustic tube. The 150 Hz sound failed to evoke avoidance responses, even at a level 30 dB above the threshold for spontaneous awareness reactions.