The next decades will see increasing levels of offshore industrial development that will lead to increased levels of noise pollution in the oceans. These sounds can have physical, physiological and behavioural effects on marine fauna in the area of activity: mammals, reptiles, fish and invertebrates can be affected at various levels depending on the distance to the sound source. The problem faced by the industry, and more generally by society, is that many economically important activities at sea are at risk because of a lack of information about the effects of anthropogenic sound on marine mammals and especially a lack of available tools to mitigate these effects. Technological developments were needed to combine the interests of the industry and the good environmental status of the oceans.

The Laboratory of Applied Bioacoustics (LAB) of the Technical University of Catalonia (BarcelonaTech, UPC) is leading an international programme entitled "Listen to the Deep Ocean Environment (LIDO)" to apply and extend developed techniques for passive acoustic monitoring of natural (e.g. rain, waves, earthquakes), biological (e.g. cetaceans, fishes, crustaceans) and artificial (man-made noises) sounds to cabled deep sea platforms and moored stations. LIDO constitutes the technical development support of the applied solutions that are now integrated and available for the administrations and the offshore industry (

The software framework developed under this programme is currently active at several sea observatories around the world: these include the ANTARES (ANTARES Collaboration, France) neutrino observatory, the OBSEA (UPC, Technical University of Catalonia, Spain) shallow water test site, the NEPTUNE (University of Victoria, Canada) network, the Kushiro and Hatsushima (JAMSTEC, Japan) observatories and the NEMO (INFN, Italy) sites. The system was also tested and implemented in autonomous gliders and towed arrays in collaboration with the NURC (NATO Undersea Research Centre, La Spezzia, Italy), autonomous radio-linked buoys, trawler-safe bottom-mounted structures and on offline recordings.

The LIDO software contains several independent algorithms that process real-time data streams. Among these, dedicated modules conduct noise assessment (that include the European Marine Strategy Directive descriptors of noise), detection, classification and localization of acoustic sources. From the acoustic data stream, LIDO characterizes and localises the detected events, produces spectrograms for live visualization and compresses audio for online access. It should be noted that the compressed audio is only provided to allow users to listen to a sound stream with minimal bandwidth usage; it is specifically not used for any scientific analysis, this latter being conducted obviously before displaying the results. The raw data is optionally stored locally if there is an interest in subsequent research.