Natural trace element enrichment in fishes from a volcanic and tectonically active region (Azores archipelago)

Seamounts, in general, are thought to support high biodiversity and special biological communities. They have been targeted by commercial fishing for demersal and pelagic fish species due to the occurrence of large aggregations in mid- and deep-water. Specimens of Phycis phycis, Helicolenus dactylopterus, Pontinus kuhlii, Beryx splendens, Beryx decadactylus, Etmopterus pusillus, Mora moro, Pagellus bogaraveo, Deania profundorum, Scomber colias and Trachurus picturatus were collected at the Condor seamount and on the slopes of Faial and Pico islands of Azores archipelago. Concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Cd and Pb were determined in muscle and liver of each individual. Values of the 11 trace elements in the two tissues of the benthopelagic and benthic specimens, from the two surveyed areas, presented a significant inter-specific variation. In general, levels were lower in muscle than in liver, and negative relations between weight and Co, Mn, Zn, As, Cd and Pb concentrations in muscle and liver of three species were found. Pagellus bogaraveo, S. colias and T. picturatus presented enhanced elemental concentrations in liver, particularly of Cd. The extremely high storage of this potentially toxic element suggests a response to high uptake of Cd and the existence of an additional natural source of Cd to the environment.