The widespread distribution of materials produced by human societies that get stranded ashore or reach the seabed is now considered a critical issue in terms of marine conservation.

This study analized litter occurrence in 68 underwater video transects performed on the middle/outer continental shelf and submarine canyon off Cap de Creus (NW Mediterranean), an area recently declared Site of Community Importance (SCI).

The results show that the density of litter was lower in the shelf, while increasing in abundance towards the deepest part of the submarine canyon. The authors hypothesize that the strong bottom currents that recurrently affect this area efficiently move litter objects from the shelf towards the deep.

It his highlighted that of all litter items, approximately 50% had a fishing-related origin, mostly longlines entangled on rocks in the canyon head and discarded trawl nets in deeper areas. They state that over 10% of the cold-water colonies observed had longlines entangled, indicating the harmful effects of such practices over benthic habitats.

The authors conclude that these results should be considered when designing mitigation measures to reduce litter pollution in Cap de Creus SCI.

Dominguez-Carrió et al. (2020) Seafloor litter sorting in different domains of Cap de Creus continental shelf and submarine canyon (NW Mediterranean Sea). Marine Pollution Bulletin 161: 111744.