Is the Loggerhead Caretta caretta a good indicator of plastic ingestion also at local scale?

The European Commission drafted the 2008/56/EC Marine Strategy Framework Directive with the aim to achieve a Good Environmental Status (GES). In 2011 Italy promoted the Loggerhead sea turtle (Caretta caretta, Linnaeus 1758) as target species for monitoring the amount and composition of litter ingested by marine animals and then it has been accepted among MSFD Indicators and under the UNEP/MAP Barcelona Convention ecological objective, at sub-regional level. 120 death loggerhead CCL ranging from 21 to 80 cm (average = 54.9 cm) have been collected stranded or by-catch along Latium and Sardinian coasts, Italy (Western Mediterranean sub-Region). Plastic ingestion has been detected with a frequency of occurrence FO=54.2%. In total, 106.138 g (dry mass) and 1103 items (abundance) of marine litter were collected with an average value of 0.892 ± 0.196 g and 9.27 ± 1.95 items. Among the impacted turtles, parts of plastic bags and other sheet fragments (USE she) were the main categories in terms of abundance (17.23 ± 3.35 items). At local level, FO%, dry mass and number of items between the two areas (Latium: FO = 79.0%, average g= 1.553 ± 0.354, average n Items = 14.76 ± 3.53; Sardinia: FO = 27.6% average g=0.173 ± 0.059, average n Items= 3.30 ± 0.95) showed significant differences and groups structure was confirmed by nonhierarchical cluster analysis. This study shows that, even if sea turtles are migratory species and marine litter move according to the current and tide, the loggerhead can give information on plastic pollution also at local scale.