Acoustic underwater noise: the segregation of frequency bands for science-to-policy advise

Underwater noise has received an increased attention at political and economic levels due to the impacts of anthropogenic activities on the environment. Metrology for underwater acoustics is still facing challenges due to conceptual and instrumental aspects. Uncertainties in calibration suggest caution in the interpretation of soundscapes when aimed to assess the status of the marine ecosystems. We discuss the challenges in the adoption of specific observational strategies and calibration procedures, in particular for the use of results to support policies that impact on the maritime traffic. We report the results of an experiment that shows how monitoring underwater soundscapes at those low frequencies identified by the Marine Strategy Framework Directive can be misleading and not supported by sound framework for the impacts of maritime traffic on ecosystems.