Plastic Waste Transport by Seabirds: Herring Gull Larus argentatus Pontoppidan, 1763 (Charadriiformes: Laridae) Acts as a Vector Transferring Anthropogenic Debris to the Coastal Zone

Seabirds occasionally ingest plastic waste at feeding sites and excrete it as part of pellets and feces over new landscapes. In this study, the quantitative aspects of plastic transfer in pellets to Salny Island (Kola Bay, Barents Sea) by herring gulls Larus argentatus are estimated. The litter, belonging to macro- and megaplastics size categories and classified as gull pellets, are shown to be accumulated in the upper plateau of Salny Island, averaging a concentration of about 0.28 kg/ha. Adult birds are supposed to feed at municipal solid waste sites and carry plastic to the island during their nesting or transit stay. According to our observations, plastic ingestion is not accompanied by a decrease in the population: an increase of the nesting density on the island by 2–4 times over the observation period of 12–14 years is shown. The phenomenon of plastic waste transport by seabirds in the Russian part of the Barents Sea is described for the first time.