Mercury and cadmium concentrations in the tissues of three species of southern albatrosses

Cadmium and mercury concentrations were measured in the tissues of 64 indiv idual albatrosses [23 wandering albatrosses (Diomedea exulans), 9 royal alb atrosses (Diomedea epomophora) and 32 shy albatrosses (Thakassarche cauta)] which were killed as by-catch in longline fishing activities between 1991 and 1994. Mercury concentrations were also determined for 33 shy albatross eggs (excluding shells). The birds were all sexed and assigned to one of tw o age classes (immature and adult). The three species exhibited differences both in overall concentrations of cadmium and mercury, and also in the pat tern of accumulation of metals with age and sex. Wandering albatrosses exhi bited the highest mercury concentrations with a mean concentration in adult liver samples of 920.0 +/- 794.1 mu g g(-1) dry weight. Shy albatrosses ha d the lowest mercury concentrations with mean concentrations in adult liver s of 36.3 +/- 21.4 mg g(-1) dry weight. The highest mercury concentration w as 1800 mu g g(-1) for an adult female wandering albatross. Cadmium concent rations were less variable, with adult royal albatrosses having the highest average concentrations (180.0 +/- 165.0 in adult kidneys) and adult shy al batrosses the lowest (40.1 +/- 20.0 in adult kidney). The highest individua l cadmium concentration was 287 mu g g(-1) for a juvenile wandering albatro ss. There was no evidence of increased accumulation of cadmium with age in any of the species, but wandering albatrosses showed higher mercury concent rations in adults than juveniles. Female wandering albatrosses also had sig nificantly higher mercury concentrations than males. The mercury contents o f the shy albatross eggs were very low, with a maximum concentration of 5.4 mu g g(-1). The results of this study are consistent with the findings of previous work on albatrosses and support the notion that the life-history s trategy of these species (i.e. long-lived with low reproductive output) may be an important determinant in the concentrations of some metals found in their tissues.