AbstractLobsters,Homarus americanus, were exposed in a flow‐through system to a sublethal concentration of zinc (Zn++) for 4 d and then transferred to flowing unspiked sea water for 7 d. The concentrations (μg/g dry weight) of Zn++after the four days of exposure were in the order gill>green gland>haemolymph>hepatopancreas>crusher tissue>crusher muscle>pincer tissue>shell>testes>heart>pincer muscle>abdominal (tail) muscle. After 7 d in unspiked water the concentration of Zn++in each of the tissues decreased, but did not return to pre‐exposure levels. In terms of the total tissue burden the level of Zn++in only the hepatopancreas continued to increase during the depuration phase. The data were analysed using a four‐compartment model with haemolymph as the “central” compartment. The exchange of Zn++between gills and water was rapid, between gills and haemolymph was somewhat slower, and between haemolymph and tail muscle was extr