Bioamplification of mercury in great skua Catharacta skua chicks: The influence of trophic status as determined by stable isotope signatures of bloodand feathers

Biomagnification of mercury was investigated via combined mercury and stabl e isotope analysis of the blood and feathers of great skua chicks from two colonies in the north-east Atlantic. There were significant positive correl ations between delta(15)N signatures and mercury concentrations in the bloo d from chicks at both colonies suggesting that dietary specialization influ ences intraspecific variability in mercury burdens. The relationships were slightly weaker in feathers and therefore blood is probably a better monito ring unit. Adult blood was also assessed and in terms of biomonitoring may provide an index of mercury intake over the whole breeding season. (C) 2000 Elsevier Science Ltd. All rights reserved.