Analysis of marine litter ingested by sea turtles stranded in Sicily: a 7-year report

Plastic pollution in marine environments, particularly the Mediterranean Sea, poses a significant threat to marine life, including sea turtles. This study investigates the ingestion of marine litter by Caretta caretta from Sicily (Italy), focusing on the quantity, quality, and seasonal variations of ingested plastic debris. From 2018 to 2024, N = 344 sea turtles (N = 237 alive, N = 107 dead; CCL mean ± sd = 49.09 ± 14.69) were recovered, of which 103 (29.94 %) (CCL from 15 to 80 cm; mean 49.09 cm) ingested litter. The study used standard protocols to analyze the gastrointestinal tracts and faecal samples of dead and live turtles, respectively. A total 255.86 g of marine litter was found in the gastrointestinal tract and most of them belonged to SHE category (27.44 %), while the less present category was POTH (2.9 %). Variability in the amount and type of litter ingested across different years was evidenced. Differences were observed in plastic ingestion across age groups, with juveniles consuming less plastic than sub-adults and adults. Subjects recovered from Central Mediterranean Sea ingested a total of 189.98 g of marine litter (28.60 % represented by SHE category); while in those recovered from Western Mediterranean Sea, the total dry mass was 65.88 g (34.33 % represented by THR category). While marine litter ingestion did not significantly correlate with reproductive cycles, it had potential sub-lethal effects, including gastrointestinal disturbances and long-term health impacts due to plastic additives. This research underlines the need for targeted conservation strategies and further studies on the long-term effects of plastic pollution on marine species and ecosystems.