Influence of phylogeny, diet, moult schedule and sex on heavy metal concentrations in New Zealand Procellariiformes

Abstract

Mercury, cadmium, zinc and copper concentrations were analysed in the liver and ludney tissues of 14 species of albatross and petrel. These birds were obtained as by-catch of the long-line tuna fishing industry in New Zealand waters, and provided a unique opportunity to compare heavy metal accumulation in a group of closely related species. Mercury levels in the liver of the wandering and royal albatrosses were among the highest recorded for free-living birds. In multiple regression analyses, much of the inter-specific variation in cadmium and mercury levels was related to the importance of Crustacea in the diet, to phylogeny, or to the duration of the moult cycle. Species in which crustacea constituted >33% of the diet had significantly lower cadmium concentrations in liver tissues, and mercury concentrations in both liver and kidney tissues, than those in which birds consumed mainly or entirely squid and fish. Thls accords reasonably well with information on relative mercury and cadmium content of prey species. After accounting for dietary variation, Procellariidae (petrels, shearwaters and prions) and Hydrobatidae (storm petrels) still exhibited higher cadrmum concentrations in the liver than Diomedeidae (albatrosses). In addition, albatrosses which took more than a year to moult accumulated higher mercury concentrations in their livers, probably because of a restricted ability to excrete mercury into growing feathers.

Trace Elements in Three Marine Birds Breeding on Reunion Island (Western Indian Ocean): Part 1—Factors Influencing Their Bioaccumulation

“…Metal levels obtained for adults in this study are generally comparable to those reported for petrels and shearwaters studied in other oceanic islands (Muirhead and Furness 1988, Stewart et al 1994, Stewart et al 1997a, Stewart et al 1999. Nevertheless, Se and Zn values observed in these birds were fairly high.…”

“…Only in the tropicbirds did juveniles have higher essential metal levels than adults. This same pattern has already been observed in various species (Kim et al 1998, Stewart et al 1999 in which the young accumulate essential elements to meet particularly high nutritional needs (Thompson et al 1996). This strategy may have evolved in order to survive the fast caused by the abandon of the fledglings by their parents several days before their first flight.…”

“…Diet is considered as one of the most important factors of trace element variability since it is the major contamination path in marine vertebrates (Stewart et al 1999, Thompson et al 1998, Kim et al 1998. Of the three Reunion species, Barau's Petrel has, by far, the highest Hg content in the studied tissues.…”

Rapidly increasing methyl mercury in endangered ivory gull ( Pagophila eburnea ) feathers over a 130 year record

“…The increase in adult ivory gulls' MeHg was similar to mesopelagic-feeding seabirds from the Azores, (Calonectris diomedea: þ1.4% per year), but less than mesopelagic specialists (Bulweira bulwerii: þ2.9% per year, Oceanodroma castro: þ4.1% per year) [68]. Procellariiformes (albatrosses, shearwaters, petrels and storm-petrels), however, tend to have higher feather Hg concentrations than other species owing to their protracted moulting periods [69,70].…”

Differences in the timing and extent of annual moult of black-browed albatrosses Thalassarche melanophris living in contrasting environments

“…As such, their study can be highly informative about responses of birds to environmental constraints. In addition, results from the chemical analysis of feathers (mostly studies of stable isotopes, trace elements and pollutants) are used increasingly to infer trends in the spatial and trophic ecology of many species, as well as to determine levels of environmental contamination (Stewart et al 1999;Hobson and Wassenaar 2008;Inger and Bearhop 2008). In such studies, obtaining reliable information on timing of moult of different feather types is not only critical for validating results, but may also allow further inferences about variation among individuals, for example in migration strategies (González-Solís et al 2011).…”