The occurrence and seasonal variation of trace metals in the scallopspecten maximus(L.) andchlamys opercularis(L.)

Abstract

A comparison has been made between the concentrations of eleven trace metals in the tissues of two species of scallops, Pecten maximus (L.) and Chlamys opercularis (L.), collected from the same area of the English Channel. Although there was considerable variation between individual animals, the mean concentrations of Ag, Co, Cr, Cu, Mn, Ni, Pb and Zn were higher in the whole body of Chlamys than in Pecten but concentrations of Al, Cd and Fe were lower. In both species, seasonal changes in the concentrations of Co, Cu, Fe, Mn, Ni, Pb and Zn were observed and, in general, the highest values were found in the autumn and winter months. These changes may be related to food supply, since concentrations were generally highest when phytoplankton productivity was low and tended to fall in the spring as productivity increased rapidly to its annual peak. Despite problems arising from individual and seasonal variation, the kidneys and digestive gland of scallops appear to have potential as biological indicators of trace metals.The results obtained for Pecten and Chlamys are compared with those in the literature for species from the family Pectinidae.