Floating debris in the Mediterranean Sea

•Results from a large-scale survey of Mediterranean floating debris are reported.•AMD densities ranged from 0 to 162.1 items/km2 (mean 24.9 items/km2).•NMD densities ranged from 0 to 117 items/km2 (mean 6.9 items/km2).•78% of all objects were of anthropogenic origin (plastic, styrofoam and others).•More than 62 million litter items are now floating on the whole Mediterranean Sea.

Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km2 and mean abundances of 24.9 AMD items/km2 and 6.9 NMD items/km2 across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km2) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km2) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km2. According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin.