SWIM - Extended period survey

The seas and oceans provide resources for a range of industrial and recreational activities, from commercial shipping to recreational boating, and from resource exploration to wind energy. All these rapidly expanding activities generate sounds, often very loud, that travel long distances through water. The growth of the ocean economy means that human-generated noise is becoming dominant in marine soundscapes worldwide. It has been observed that this can be very harmful to marine life, but the extent of the damage has not been quantified. Scientific knowledge of underwater noise pollution is growing rapidly but remains limited; further research is needed to provide policymakers with essential guidelines for the sustainable exploitation of marine resources. Future noise pollution models will need to include precise information on specific noise sources, the propagation of elastic waves in marine environments, and the impact of noise on individual marine species. SWIM helps us understand how new wind farms could affect toothed whales, depending on their characteristics (such as fixed or floating turbines) and their location.

The plan for the extended perios survey was to deploy two bottom recorders at two locations defined by the transect strategy to enable long-term understanding of how variations in turbine speed, caused by changes in wind, affect noise generation. At the same time, the aim was to understand how that noise propagates, as the synchronised recorders would allow the distance between them to define the amplitude loss of the noise. For this survey, Nauta Scientific was contracted. Nauta Scientific developed independent seabottom recorders that can be deployed and recovered up to two months later.