This study estimates levels of marine litter including plastics (macro-, meso- and microplastics) in sediments collected in shallow marine water from Croatia (Central Adriatic Sea). Selected sampling areas are characterized by different human pressure: Silba is highly stressed by tourism while Grebena is listed as marine protected area (MPA) of future institution. Obtained results on marine litter in sediments are correlated to ecological features recorded in each sampling site. Marine litter in collected sediments ranged within 180–528 items/kg d.w. Macroplastics were not recorded while mesoplastics were 1.3–4.8%. On a general basis, fibres are higher than microplastics. In Južni Greben, level of fragments higher than fibres was recorded. A slight significance of the factor “water depth” was evidenced by the statistical analyses exploring relationships among marine litter and ecological features. Furthermore, Silba and Grebena Islands showed a significant different assessment of size, shape and colour features. These results suggest different sources/dynamics affecting marine litter recorded in marine areas stressed by tourism compared to MPA.
