The general aim of the CESMEC mission (Cetacean Soundscapes in the Mediterranean Cetacean Corridor) is to advance the development of near real-time automated systems using unmanned vehicles to simultaneously monitor cetaceans, ship-based activities and the marine environment in large marine protected areas. We have two specific objectives: 1) Monitor the presence of cetaceans in the Mediterranean Cetacean Corridor, with a major focus on fin whales and dolphins. 2) Monitor underwater noise to characterize the acoustic footprint of ship-based activities.

Large marine protected areas are increasingly being implemented across the oceans. The dynamic nature of pelagic environments presents unique challenges for their management. Conducting surveillance and monitoring in vast areas requires the development of innovative and cost-effective methods. The Mediterranean Cetacean Corridor constitutes a hotspot for marine megafauna under pressure of multiple human threats. It represents an area of high oceanographic interest for assessing climate-driven effects.

Wide-ranging marine megafauna species are likely to experience multiple human threats across the seascape. Highly mobile species are threatened by different ship-based activities. For instance, commercial shipping can have serious impacts on marine megafauna due to generated underwater noise and ship strikes. Recently, gliders have been equipped with hydrophones, becoming excellent platforms for near real-time passive acoustic monitoring of cetaceans or anthropogenic noise. In contrast to static hydrophones, which provide extended time series for specific locations and depths, ocean gliders can be used to measure ambient noise at multiple depths and locations. This proposal will demonstrate the potential use of gliders for simultaneously monitoring underwater noise and the presence of cetaceans in large marine protected areas regardless of the ocean and weather conditions. The outputs of this project encompass the assessment of marine biodiversity and underwater noise, thereby directly contributing to the descriptors 1 and 11 of the European Marine Strategy Framework Directive.

The proposed study will be conducted in the Mediterranean Cetacean Corridor (MCC), a large marine protected area. MCC constitutes a migratory corridor used by many species of cetaceans, recently approved as a Specially Protected Area of Mediterranean Importance. An ocean glider equipped with a hydrophone and oceanographic sensors will be deployed on a 30-day mission to detect the presence of cetaceans, characterize the 3D soundscape and sub-surface oceanographic variables. Collected data will then be compared with concurrent ship-based surveys, near-real time fin whale distribution models and underwater noise models derived from AIS data. Water samples for eDNA will be collected near the three vertexes of the triangular path (i.e. Sóller, Vilanova i la Geltrú and Columbretes Islands). In addition, in the latest two locations, visual surveys with aerial drones will be conducted by the research team