Assessment of natural and anthropogenic sound sources and acoustic propagation in the North Sea

For a proper (national) implementation of the European Union’s ambitious Marine Strategy Framework Directive, it is required that the impact of anthropogenic activities on the North Sea environment is assessed thoroughly. One of the effects of the use of the North Sea by humans is the generation of underwater sound. Sound propagates over longer distances in water than in air. The impact of anthropogenic underwater sound sources could therefore be serious. At this time, there is insufficient information on the underwater sound environment in the North Sea to make an impact assessment. The information on anthropogenic sources of underwater sound, i.e. the sound characteristics and source levels, is by no means complete. Once this information becomes available, the next challenge is to predict correctly how the sound propagates in the shallow water of the North Sea, i.e. to find out the sound footprint of individual anthropogenic or natural sources of sound. The research reported on in this document aims at making an inventory of the existing knowledge on the underwater sound environment and identifying the gaps. In the next steps towards an impact assessment, there is insufficient information on the physiology and behaviour of the marine fauna of the North Sea. There is also a lack of knowledge on the effects of the various anthropogenic sources of sound on the ecosystem of the North Sea, both individually and cumulatively.