T0573 Risk caused by plastic pollution on marine ecosystems: a seascape-driven approach

Plastic pollution is cause of increasing scientific and social concern due to its pervasiveness and persistence, in particular in the marine environment. The Mediterranean Sea (MS), one of the ecoregions most impacted by human activities worldwide, is affected by marine litter, with measured plastic concentrations comparable with those typically found in oceanic gyres. At the same time, the MS is a semi-enclosed basin hosting about 7% of the world’s marine biodiversity, including several endangered species. In our work, we propose a methodology to assess risk of pollution from plastic waste within the largest marine protected area of the MS (the Pelagos International Sanctuary for the Protection of Mediterranean Marine Mammals, North-Western Mediterranean), which includes the most important feeding grounds of the fin whale {it Balaenoptera physalus}, an endangered species that is heavily impacted by microplastic ingestion. Using a quantitative and data-driven approach, we modelled a decade (2000-2010) of marine plastic litter advection patterns released from different sources (i.e. coastlines, major rivers and maritime shipping routes). Risk of exposure of fin whales to plastic pollution has been evaluated by interlacing litter distribution maps, generated from oceanographic modelling, with maps of suitable habitats by elaborating seascape data, i.e. satellite chlorophyll data and bathymetry, within species-specific visited areas. Our modelling results show that all the three main sources of plastic litter clearly contribute to impacting cetaceans in the Sanctuary, yet in a quantifiable different manner. The proposed procedure can potentially be extended to assess the risk caused by plastic pollution in other areas or on other taxa, thus informing targeted actions to tackle marine litter.