Oceanic plastic pollution caused by Danish seine fishing in Norway.

Wear and tear on fishing gear is a sparsely investigated source of microplastic pollution in the sea. In Norway, Danish seine ropes and trawls are the fishing gears that contribute most to this pollution. The main reason for this pollution is that the seine ropes are dragged along the seabed over a considerable distance, creating a friction force that results in high ropes wear. This note reports the findings after examining the wear of Danish seine ropes used in Norwegian fisheries. The results show that, in Norway alone, an average of 77 to 97 tons of plastic will be added to the sea annually due to this specific fishing gear. Aggregated to include all fly dragging, anchor seining, and pair seining globally, this number is estimated to be about 311 tons per year.