It has been known for a long time that marine turtles are impacted by marine litter, by ingestion or entanglement. These species are even recognized as indicators of pollution. Today, we deplore a concrete example of impact, and this time we know the source.
At the sea turtle treatment center of Grau du Roi (CESTMed), a loggerhead turtle Caretta caretta accidentally caught by a trawl, expelled in its faeces one of the « filter media » lost south of Naples last February. 2 monthes earlier, at necropsy, in the digestive tract of another turtle found dead at the Camargue regional natural Park, a filter was found by the French Mediterranean Sea Turtle Network (SHF-RTMMF). The 2 turtles were found in the same area, around the same time.
The 45 mm diameter filters, manufactured by Veolia, first mass landed on the Tyrrhenian coast, from Salerno to Liguria and Sardinia: millions of plastic discs used in wastewater treatment plants, lost and dispersed after a structural failure of a tank in the Gulf of Salerno. They then drifted towards Corsica and the Gulf of Lion.
This odyssey, followed by the LIFE CLEANSEA project, IFREMER , SURFRIDER etc, made it possible to visualize and follow the destiny of plastics towards the west of the Mediterranean Sea, which fits the dispersal path predicted by a model realized by the LaMMA.
Unfortunately, it is likely that more cases will be reported in next weeks or months, whether it be on turtles or other organisms that have confused these filters with food. A survey has been intiated by MNHN GTMF through the Medturtle discussion list.
More information available on GTMF website.