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 re presentative of an offshore pelagic food web in the Gulf of Genoa, Ita ly: Meganycthiphanes norvegica, Gennadas elegans, Pasiphaea sivado, Pa siphaea multidentata and Aristeus antennatus. According to their preda tor-prey relationships, they represent three trophic levels in the Lig urian Sea. The concentrations of total and organic mercury increase wi th the trophic levels and with the weight of the specimens (except in G. elegans and in females of A. antennatus). However, at higher trophi c levels the specimens are also larger. Only in P. sivado, do levels o f inorganic mercury increase significantly (P = 0.001) with the size o f the specimens. The ratio between organic mercury and total mercury d id not increase with the trophic level.