Given our projects in the North Sea and our work on Environmental Impact Assessments (EIA) and with the development of the iPCoD framework, we’re always particularly interested when new research comes to light on how porpoises respond to noise. Today is one such day of interest!
The team of researchers at Aarhus University behind the DEPONS project – which looks to further our knowledge of the effect of disturbance on the North Sea harbour porpoise population – explored how five porpoises, fitted with radio transmitting tags to track their horizontal movement and dive behaviour responded to exposure to seismic air gun sounds. The authors found:
We exposed porpoises to airgun pulses at ranges of 420–690 m with noise level estimates of 135–147 dB re 1 µPa2s (sound exposure level), one individual displayed rapid and directed movements away from the exposure site and two individuals used shorter and shallower dives compared to natural behaviour immediately after exposure. Noise-induced movement typically lasted for less than or equal to 8 h with an additional 24 h recovery period until natural behaviour was resumed. The remaining individuals did not show any quantifiable responses to the noise exposure.
You should check out the full paper here.
Floris M. van Beest, Jonas Teilmann, Line Hermannsen, Anders Galatius, Lonnie Mikkelsen, Signe Sveegaard, Jeppe Dalgaard Balle, Rune Dietz, Jacob Nabe-Nielsen. 2018. Fine-scale movement responses of free-ranging harbour porpoises to capture, tagging and short-term noise pulses from a single airgun. R. Soc. open sci. 2018 5 170110; DOI: 10.1098/rsos.170110. Published 10 January 2018.