Abstract
Ordinary fishing activity is a source of microplastics to the sea that is often overlooked and scarcely reported in the literature. In this paper, we estimate the number of microplastics in the ocean that originates from the wear and tear of different fishing gear used during ordinary, commercial fishing. The wear comes mainly from rope abrasion caused by the haulers and gear dragged along the sea bottom. The types of fishing gear considered are pots, gillnets, longlines, Danish seine, and trawls. Our calculations show that about 208 tons of microplastics are produced annually from the Norwegian fishery. Globally, it sums to 4 622 tons annually. However, the calculations have several questionable parameters, and these numbers must be considered a first rough estimate of the generated microplastics. More research is needed to get better estimates, particularly regarding trawl dolly ropes