Mercury, cadmium, and lead content in demersal sharks from the Macaronesian islands

Abstract

The overexploitation of shark and ray fishing as well as anthropogenic pollution in the sea has led to a large decline in their population, and because sharks occupy a high trophic position in the ecosystem, they could have high concentrations of heavy metals such as Hg, Pb, and Cd. This study is based on seven species of demersal sharks which were caught in the Macaronesian archipelagos (Tenerife, Gran Canaria, and the Azores Archipelago). Hg and Pb concentrations were found in the present study to be below those reported in other comparative studies, with the highest reported values of Hg and Pb being 281,738 μg/kg for Pb in Deania profundorum (Smith & Radcliffe, 1912) and 264,30 μg/kg for Hg in Centrophorus uyato, Rafinesque, 1810. As for Cd, the values found here are higher than those in the literature, the highest reported concentration being 120.36 μg/kg in Centrophorus squamosus (Bonnaterre, 1788).