Effects of anthropogenic noise on marine life

Peter L. Tyack
Sea Mammal Research Unit, Biology Department, University of St Andrews, KY16 8LB UK
plt@st-andrews.ac.uk

There has been growing recognition that humans during the industrial era have been introducing noise into wildlife habitats, and that this increase in noise may make it more difficult for animals that use sound for communication, orientation and echolocation. Noise can disrupt behavior, cause physiological stress, and in severe cases, can injure or kill animals. Studies of heari ng show that it takes considerable sound energy to cause a direct physical effect. However, it became clear about 2000 that atypical mass strandings of beaked whales coincide with naval sonar exercises. The prevailing hypothesis was that sonar triggers a behavioral reaction in beaked whales which may injure or kill whales through decompression sickness and/or stranding. I will describe the use of acoustic recording tags to document how these whales feed at depth, and how sonar disrupts foraging dives. Quantification of the sound levels  that disrupt behavior changed US regulatory thresholds for disturbance in these species. However, chronic effects of  oise on wildlife may have greater impacts on populations and ecosystems than rare lethal events. A dominant source of noise is human transportation, from vehicles a nd aircraft putting sound in the air, to ships putting sound into the ocean. The first alarm about the effects of sound on marine life involved calculations that the noise of ships could mask the calls of whales, reducing the range over which they could communicate from hundreds down to tens of  kilometers. If this disrupted the mating system of whales, it could affect populations, especially those decimated by whaling. Acoustic measurements have shown that some whale calls can be detected hundreds of km away, but we still do not know how significant ship noise is in masking the calls of whales, nor if it affects reproduction. What we do know is that when whales are exposed to noise, they can alter their calls to improve the chances that the call will be detected. Noise is ubiquitous in communication, and I suggest that some mechanisms to compensate for noise represent primitive forms of vocal learning that may have enabled more complex forms of learning in the evolution of animal communication systems.

Recent publications:
Macfarlane, N., Howland, J., Jensen, F. & Tyack, P. L. (2015). A 3D stereo camera system for precisely positioning animals in space and time. Behavioral Ecology and Sociobiology.

Allen, A., Schanze, J., Solow, A. &Tyack, P. L. (2014). Analysis of a Blainville's beaked whale's movement response to playback of killer whale vocalizations. Marine Mammal Science. 30, 1, p. 154-16.

De Ruiter, S. L., Southall, B. L., Calambokidis, J., Zimmer, W. M. X., Sadykova, D., Falcone, E. A., Friedlaender, A. S., Joseph, J. E., Moretti, D., Schorr, G. S., Thomas, L. & Tyack, P. L. (2013). First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonar. Biology Letters. 9, 4, p. 1-5.

Contact: Aurélie Celerier aurelie.celerier@cefe.cnrs.fr
Contact du Comité SEEM: seem@services.cnrs.fr.