MECHANISMS OF COPPER TOXICITY IN THE SHORE CRAB, CARCINUS-MAENAS .1. EFFECTS ON NA,K-ATPASE ACTIVITY, HEMOLYMPH ELECTROLYTE CONCENTRATIONS AND TISSUE WATER CONTENTS

This study was initiated to further elucidate mechanisms responsible for copper toxicity in the hyperregulating shore crab, Carcinus maenas (L.). Crabs, collected in the Odense Fjord, Denmark between September 1989 and May 1990, were exposed to 10 ppm copper (II)chloride in 10 ppt salinity at 15-degrees-C for up to 1 wk prior to measuring gill Na,K-ATPase activity, haemolymph sodium and potassium concentrations and fr. wt/dry wt ratios. Copper exposure reduced haemolymph sodium concentration by 40% and gill Na,K-ATPase activity by 50 to 60% after 1 wk. Haemolymph potassium levels exhibited variable responses. It is concluded that inhibition of gill Na,K-ATPase activity was primarily responsible for reductions in haemolymph electrolyte levels but that this was possibly not the principle cause of morbidity and mortality.