Top 10 marine litter items on the seafloor in European seas from 2012 to 2020.

We studied the ten most frequently encountered litter items from the seafloor in European seas to advance actions and inform future mitigation measures to reduce marine litter and the associated social, economic and environmental impacts it has on European seas and beyond. Data were collected during trawl surveys from 2012 to 2020 as part of national and regional marine litter monitoring programmes in the Greater North Sea (5652 trawls), Celtic Seas (3505), Bay of Biscay (651), and Baltic Sea (3688). A Bayesian approach is used to quantify the variation in the item rankings. Overall, plastic items predominate in the top positions in each area. Synthetic rope, plastic sheets, monofilament fishing line and plastic bags occupy four of the top five positions for each of the Greater North Sea, Celtic Seas and the Bay of Biscay. Items from fishing and rope (representing mainly other maritime activities) are strongly represented in the top ten lists from three of our four areas, with synthetic rope, fishing nets, and tangled and untangled monofilament fishing line listed in the top seven positions for the Greater North Sea, Celtic Seas and the Bay of Biscay. The top ten items in the Baltic Sea are of a different profile to the other regions, but the most commonly caught items are still predominantly plastic, with plastic sheets, other plastic items and plastic bags occupying three of the top four positions. The findings in this study highlight the need to address sea-based sources to try and eliminate litter from fishing and maritime activities. Measures such as improved port reception facilities, marking of fishing gear, promoting reporting of the loss of fishing gear and increasing public awareness should be introduced.