Ecotoxicological status of Tursiops truncatus in the Mediterranean Sea and in the Gulf of California (Sea of Cortez-Mexico) using skin biopsy as diagnostic tool

The main objective of this study was to apply a sensitive nonlethal “multi-trial-diagnostic-tool” in skin biopsy of common bottlenose dolphin (Tursiops truncatus), combining molecular biomarkers, such as two isoforms of the cytochrome P450 (CYP1A1 e CYP2B) with analysis of lipophilic contaminants, such as hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDTs), polychlorobyphenils (PCBs) and polycyclic aromatic hydrocarbons (PAHs), to evaluate the toxicological status of this odontocete in 4 Mediterranean areas (Isle of Vis; Isle of Lampedusa; Isle of Asinara; and Strait of Gibraltar) and in the Sea of Cortez (Mexico). These surveys allowed to estimate the “toxicological stress” of the specimens of the different populations, in particular considering that the Sea of Cortez (Mexico) is a remote area and therefore exposed to a significantly lower anthropic pressure than the Mediterranean Sea. The results of this study reveal that the bottlenose dolphin population most affected by OCs and PAHs contamination is the one sampled in the Strait of Gibraltar. In the specimens of this area the highest levels of CYP1A1 were also found. Lower levels of OCs were found in the specimens sampled in the Sea of Cortez where, however, the highest levels of CYP2B were detected. The lowest average values of PAHs were measured in skin biopsies of the specimens sampled in the Adriatic area and in the area of the Isle of Asinara. In conclusion this preliminary data suggest the potential application of the proposed diagnostic approach as a powerful method to define the toxicological status of this marine top predator and suggest the application of this methodology in the future EU Marine Strategy.