Assessing the environmental risks of marine seismic surveying: Latest insights from sonar

The production of underwater sound is more and more considered to be an environmental risk. This has already been the case for military sonar for more than a decade, as sonar was identified as a possible cause of marine mammal strandings. The approach we adapted for military sonar is the following. The risk is characterized by computing the exposure (sound produced by the sonar) in an area around the source and by coupling that information to the effects it causes on a certain animal species. The risk is then quantified by taking into account the probability of the presence of that species in the area. If too large, the risk can be mitigated. We observe a trend of shifting the focus from individual disturbance to more general population consequences. A similar approach is advised to characterize the risks involved in the use of airguns in seismic acquisition.