Plastic monitoring in seabirds nests

The Mediterranean Science Commission (CIESM) launched an initiative in 2021 to monitor marine litter in the nests of the European Shag (Phalacrocorax aristotelis). This species has the particularity to use marine litter collected at sea as nest-building material, which would make it most appropriate as an indicator of marine litter pollution in nearby coastal waters.

European Shag (Phalacrocorax aristotelis)
(photo: H. Foxonet)
Example of a nest containing marine litter items (photo: B. Cadiou)

This initiative aims to test the relevance of an original indicator of coastal pollution through a relatively simple, once-a-year monitoring using a standardized protocol across the Mediterranean basin and adjacent coasts. The resulting index could then be used as a tool for the protection of threatened MPAs and coastal habitats.

2021 (pilot survey) :
– 4 countries (Croatia, France, Greece, Portugal)
– 25 colonies/sub-colonies
– 439 nests visited
– 20% of the nests included marine litter

2022 :
– 4 countries (Croatia, Cyprus, France, Portugal)
– 28 colonies/sub-colonies
– 462 nests visited
– 10% of the nests included marine litter

Marine litter found in the nests mostly consist of plastic bags, fishing gear and ropes, and a diversity of debris of various origins and colors.