Résumé
The contents of the digestive tracts of 21 loggerhead turtles (20 juveniles and 1 adult) collected along the French Mediterranean coast were extracted during necropsies. Hard and soft items were collected and identified by visual observation. A 15-mL sample of the liquid from the rinsed contents of each digestive tract was collected and dietary DNA (dDNA) was extracted and amplified with a 18S universal eukaryotic primers. The obtained reads were compared with taxonomic DNA reference database. Ten taxonomic groups (annelids, cnidarians, crustaceans, echinoderms, fish, insects, molluscs, plants, poriferans and tunicates) were identified with visual observation and eight (ctenophores, cnidarians, crustaceans, fish, molluscs, poriferans, tunicates and plants) with dDNA metabarcoding. Annelids, echinoderms and insects were detected only with visual observation, whereas ctenophores were detected only with dDNA. The two methods were complementary to cover the range of prey, with more soft-bodied organisms detected by dDNA and more hard-shelled organisms detected by visual observation. The increased use of the dDNA metabarcoding method will help compare sea turtle diets of the different stages such as juveniles and adults, or specimens living in different areas, despite the limitations and complexity associated with its use.