Total and organic mercury concentrations in offshore crustaceans of the Ligurian Sea and their relations to the trophic levels

Total mercury and organic mercury were measured in five crustaceans representative of an offshore pelagic food web in the Gulf of Genoa, Italy: Meganycthiphanes norvegica, Gennadas elegans, Pasiphaea sivado, Pasiphaea multidentata and Aristeus antennatus. According to their predator-prey relationships, they represent three trophic levels in the Ligurian Sea. The concentrations of total and organic mercury increase with the trophic levels and with the weight of the specimens (except in G. elegans and in females of A. antennatus). However, at higher trophic levels the specimens are also larger. Only in P. sivado, do levels of inorganic mercury increase significantly (P = 0.001) with the size of the specimens. The ratio between organic mercury and total mercury did not increase with the trophic level.