• Session: 03. Acoustic Monitoring of Ocean Environments and Processes: Biology, Ecology, Geophysics and Man-made activities
    Organiser(s): Ratilal Purnima, Miksis-Olds Jennifer
    Paper ID: 751
    Author(s): Davidsen Jan G., Dong Hefeng, Linné Markus, Andersson Mathias H., Piper Adam, Prystay Tanya S., Hvam Eivind B., Thorstad Eva B., Whoriskey Frederick, Cooke Steven J., Sjursen Aslak D., Rønning Lars, Netland Tim C., Hawkins Anthony D.
    Presenter: Dong Hefeng
    Presentation type: oral
    Abstract: It has been great concern that increasing anthropogenic underwater noise may have negative effect on fish and other marine life. Airguns used for seismic exploration by the oil and gas industry generate acute, repetitive and intense sounds. The sound impulse generated by an airgun is omnidirectional and has greatest energy at low frequencies between 20 and 50 Hz. Depending on sound intensity and proximity, fish that are exposed to the noise from seismic airguns may incur physical damage, physiological stress responses and behavioural changes. Physiological stress responses or behavioural reactions may inhibit activities like feeding and spawning and, hence, negatively impacts on fish populations. \n This paper presents a controlled experiment to study the effect of sound exposure from a seismic airgun on Atlantic fish: cod and saithe. The captured fish (20 cod and 11 saithe) were tagged with biologger to measure a heart rate and body temperature and acoustic transmitter to monitor fish movement. The tagged fish were released in a sea cage (50 m diameter x 25m depth). Various sensors were deployed around the cage for measuring fish movement, ambient noise, airgun sound pressure, particle motion and water temperature and salinity. An airgun towed by a boat fired shots when the boat sailed towards the cage. Ambient noise recorded during 18 days were high and variable partly due to storm weather conditions during the experiment. The data analysis demonstrates that heart rate in cod declines with airgun shooting, but they quickly recovered or habituated after repeat exposure. The sound exposures may not be associated with longer-term deleterious changes. Saithe did not show an altered heart rate related to the sound exposures, but the sample number was low. Both cod and saithe exhibited a flight response to sound exposure. This study suggests that the fish became habituated to sound exposure.
  • Corresponding author: Dr Dong Hefeng
    Affiliation: Norwegian University of Science and Technology
    Country: Norway