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One of the major gaps in the knowledge of sea turtle population dynamics is survival probability, in particular of juveniles, which represent the bulk of the population and whose survival has the greatest effect on population growth. One of the major global threats to sea turtles is incidental bycatch, although not all animals die in the process. This is particularly acute for the loggerhead sea turtle (Caretta caretta). Here fisheries-dependent monitoring is used to seek insights into patterns of survival at multiple Mediterranean foraging areas: north and south Adriatic, north Ionian, and the Tunisian shelf. Annual survival probability was estimated using the catch curve method. Size data of 2191 loggerhead turtles ranging from 19 to 92cm curved carapace length were converted to age according to eight age-size curves available from the Mediterranean Sea. The mean annual survival probabilities for the four areas were heterogeneous and ranged between 0.710 and 0.862. Results suggest that the survival probabilities for Mediterranean loggerheads, especially in some areas, are lower than would be expected from a healthy population. This is of particular concern for the Greek rookeries, which appear most affected by anthropogenic mortality occurring in the study areas. This supports the implementation in those areas of measures mitigating the main threats, notably bycatch

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The principal aim of the present study was to develop and apply novel ex vivo tests as an alternative to cell cultures able to evaluate the possible effects of emerging and legacy contaminants in Caretta caretta. To this end, we performed ex vivo experiments on non-invasively collected whole-blood and skin-biopsy slices treated with chrysene, MEHP, or PBDE-47. Blood samples were tested by oxidative stress (TAS), immune system (respiratory burst, lysozyme, and complement system), and genotoxicity (ENA assay) biomarkers, and genotoxic and immune system effects were observed. Skin slices were analyzed by applying a 2D-PAGE/MS proteomic approach, and specific contaminant signatures were delineated on the skin proteomic profile. These reflect biochemical effects induced by each treatment and allowed to identify glutathione S-transferase P, peptidyl-prolyl cis-trans isomerase A, mimecan, and protein S100-A6 as potential biomarkers of the health-threatening impact the texted toxicants have on C. caretta. Obtained results confirm the suitability of the ex vivo system and indicate the potential risk the loggerhead sea turtle is undergoing in the natural environment. In conclusion, this work proved the relevance that the applied ex vivo models may have in testing the toxicity of other compounds and mixtures and in biomarker discovery.