Field evidence of metal transfer from invertebrate prey to an intertidal predator, Thais clavigera (Gastropoda : Muricidae)

The predatory gastropod mollusc Thais clavigera inhabiting two shores withi n the Cape d'Aguilar Marine Reserve, Hong Kong, had very different diets. O n an exposed shore the barnacle Tetraclita squamosa dominated the diet. In contrast, on an adjacent sheltered shore diet was more varied. A variety of molluscs were preyed upon year round and the temporally patchily distribut ed pulmonate limper Siphonaria japonica and the barnacle Balanus amphitrite dominated the diet in winter and summer, respectively. This differing feed ing ecology over a limited geographical area provided a unique opportunity to study the importance of dietary uptake of cadmium, copper and zinc in an unpolluted environment. Thais clavigera feeding on either barnacles or, ma inly, gastropods will receive a significant input of trace metals from such sources. Thais clavigera collected from the exposed shore had higher zinc body concentrations (313 +/- 14 mu g g(-1)) compared to sheltered shore con specifics (261 +/- 11 mu g g(-1)), attributed here to the higher zinc conce ntrations in their barnacle prey. Conversely, T. clavigera collected from t he sheltered shore had higher copper body concentrations (310 +/- 22 mu g g (-1)) compared to exposed shore conspecifics (183 +/- 14 mu g g(-1)) attrib uted to the higher proportion of haemocyanin-containing gastropods in the d iet. No difference in accumulated T. clavigera body cadmium concentrations were observed in individuals with differing feeding ecologies. Cadmium body concentrations of prey were, however, similar and the route of cadmium upt ake in this gastropod, therefore, remains unclear. (C) 2000 Academic Press.