Behavioral responses by grey seals (Halichoerus grypus) to high frequency sonar.
The use of high frequency sonar is now commonplace in the marine environment. Most marine mammals rely on sound to navigate, and for detecting prey, and there is the potential that the acoustic signals of sonar could cause behavioral responses. To investigate this, we carried out behavioral response tests with grey seals to two sonar systems (200 and 375 kHz systems). Results showed that both systems had significant effects on the seals behavior; when the 200 kHz sonar was active, seals spent significantly more time hauled out and, although seals remained swimming during operation of the 375 kHz sonar, they were distributed further from the sonar. The results show that although peak sonar frequencies may be above marine mammal hearing ranges, high levels of sound can be produced within their hearing ranges that elicit behavioral responses; this has clear implications for the widespread use of sonar in the marine environment.
Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, Fife KY 16 8LB, United Kingdom; SMRU Marine, New Technology Centre, North Haugh, St Andrews KY 16 9SR, United Kingdom. Electronic address: gdh10@st-andrews.ac.uk.
Gordon D
GD
Hastie
Centre for Research into Ecological and Environmental Modelling, University of St Andrews, St Andrews, United Kingdom.
Carl
C
Donovan
Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, Fife KY 16 8LB, United Kingdom.
Thomas
T
Götz
Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, Fife KY 16 8LB, United Kingdom.
Vincent M
VM
Janik
D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects*; D006309:Hearing; D046048:Seals, Earless / Q000502:physiology*; D013016:Sound / Q000009:adverse effects*; D013018:Sound Spectrography / Q000009:adverse effects*; D013550:Swimming
Acoustic; Avoidance; Behavior; Hearing; Pinnipeds