Food resources influence levels of persistent organic pollutants and stable isotopes of carbon and nitrogen in tissues of Arctic foxes (Vulpes lagopus) from the Pribilof Islands, Alaska

Abstract

The Arctic fox (Vulpes lagopus) is a small canid with a circumpolar Arctic distribution. Several subspecies are recognized, including a subspecies known as the Pribilof fox (V. l. pribilofensis) endemic to the Pribilof Islands of Alaska, USA. Pribilof fox tissues were collected from the islands of St. Paul (n = 38) and St. George (n = 13). Levels of persistent organic pollutants (POPs) and stable isotopes of carbon and nitrogen were measured and the findings related to sex, age class, island and access to anthropogenic food resources using ANOVA and principal component analysis. The rank order for POPs in fat was polychlorinated biphenyls (ΣPCBs) > chlordanes (ΣCHLs) ≫ hexachlorocyclohexanes (ΣHCHs) > DDTs (ΣDDTs) > hexachlorobenzene (HCB) ~ polybrominated diphenyl ethers (ΣPBDEs). Adult females had lower mean levels of most POPs (ΣPCBs, ΣCHLs, ΣHCHs, ΣDDTs) and lower δ15N values than adult males. Foxes on St. Paul had significantly higher levels of most POPs than those on St. George, though St. George foxes were significantly higher in HCB. Foxes with high probability of access to anthropogenic foods had significantly lower levels of ΣDDTs and lower δ15N values than foxes with a low probability of access. The observed differences in contaminant and stable isotope levels were consistent with fox use patterns of different food resources. POP concentrations in the tissues of some Pribilof foxes, especially from St. Paul, were higher than those associated with thresholds for adverse health effects. POPs may therefore be a factor for consideration in the conservation of Pribilof foxes.