BRIEF COMMUNICATIONS Mother-embryo isotope (δ15N,δ 13C) fractionation and mercury ( Hg) transfer in aplacental deep-sea sharks

Stable carbon (C-13) and nitrogen (N-15) isotopic values and total mercury (Hg) concentrations were analysed in muscle and liver of mothers and embryos of two aplacental shark species, Squalus megalops and Centrophorus moluccensis. Embryos of the two species had similar or lower isotopic values than their respective mothers, the only exception being for C-13, which was higher in the liver of C. moluccensis embryos than in their mothers. Hg concentrations were systematically lower in embryos compared with their mothers suggesting a low transfer of this element in muscle and liver.