VARIATION AMONG POPULATIONS IN THE RESISTANCE OF MYTILUS-EDULIS EMBRYOS TO COPPER - ADAPTATION TO POLLUTION

The effects of copper on embryo development were found to differ between populations of the mussel Mytilus edulis L. (Mollusca: Bivalvia). Concentrations of copper which caused significantly increased rates of abnormality, and thus decreased yields of normal larvae, in populations from an unpolluted site (Menai Straits, Wales, UK) and to a lesser extent in an intermediately polluted site (Oosterschelde, The Netherlands) did not affect development of embryos from a polluted-site (Westerschelde, The Netherlands) population. Crosses indicated that tolerance was mostly maternally determined, but there is also evidence of a paternal, i.e. genetic, effect. An appreciable quantity of background, non-treatment, embryo abnormality appeared to be sperm-mediated.