Seafloor litter in Dutch benthic dredge samples 2021-2022 : a pilot study

The major result is that dredge sampling collects far more litter items than current techniques monitor litter on the seafloor on the Dutch Continental Shelf. The results shows that the actual number of seafloor litter items are much larger than estimated using the current techniques. This is an important warning to policy makers, scientists and the public not to underestimate the true level of seafloor litter pollution.

The result of this pilot study is the very large difference in the total number of litter items estimated per km2 compared to fishing techniques with the Grand Ouverture Verticale (GOV) (x900) and beam trawl (BT) fishing nets (x400). This result can only to a small extent be explained by a larger sampling depth of 20 cm, compared to an estimated 0 and 2 cm for GOV and beam trawling, respectively.