Temporal trend of mercury in relation to feeding habits and food availability in arctic foxes (Vulpes lagopus) from Svalbard, Norway

Abstract We investigated the temporal trend of mercury (Hg) in arctic foxesfrom Svalbard, Norway sampled in the period 1997–2014 ( n  = 109, from 11 trapping seasons). We used linear models to investigate the effect of trapping season, feeding habits ( δ 13 C), food availability from marine and terrestrial ecosystems(reindeer carcasses and sea icecover), sex, age and body condition on liver total Hg (THg) levels. Liver THg levels increased in arctic foxeswith 7.2% (95% CI: 2.3, 9.6) per year when the concentrations were adjusted for variation of δ 13 C, sea icecover, and reindeer carcasses, whereas the raw annual trend was 3.5% (CI: −0.11, 7.2). However, the THg levels in arctic foxesfrom Svalbard are still lower than other marine mammals. We also demonstrate that arctic foxterrestrial food consumption is important for lowering the overall THg levels in this species.