Investigating local trawl fishing as a source of plastic beach litter

This paper uses a particle tracking model to simulate the distribution of fishing-related marine-sourced plastic litter from demersal trawling activities along the Atlantic coast of Scotland. The modelled fishing litter dispersed widely across the region, with ∼50% of the particles beaching along the northwestern Scottish coast after a year-long simulation. The model was tuned using observations of beached litter loadings along the same coastline to estimate the annual input, by mass, of small (<1 kg) plastic litter. Model results suggest that between 107 g and 280 g of small fishing-related litter enters the ocean per hour of fishing, resulting in an estimated 234 t to 614 t of small fishing-related litter entering the ocean annually on the Scottish west coast. These results suggest that fishing on the Atlantic coast of Scotland may be a significant source of marine plastic. However, more modelled and observational data are required to reduce uncertainty.