Mercury and stable isotope (δ13C and δ15N) trends in decapods of the Beaufort Sea

To date, limited data are available on mercury (Hg) concentrations in Arctic benthos. It is important that we establish baseline Hg concentrations in benthic communities to improve our understanding of Hg within the Arctic marine ecosystem because they are food sources of key species, such as beluga whales, which are consumed by Inuit as a part of their traditional diet. In this study, we present Hg concentrations (total and monomethyl-THg and MMHg) in three shrimp species in the Canadian Beaufort Sea region: Eualus gaimardii, Sclerocrangon boreas and Sclerocrangon ferox. We compared the variability between the three species and investigated whether it could be accounted for by regional (depth, latitude, longitude) or biological indices (stable isotope, SI, ratios of nitrogen and carbon). E. gaimardii exhibited the lowest mean delta N-15 and delta C-13 values and mean THg and MMHg concentrations, whereas S. boreas had the highest mean delta N-15 value and S. ferox had the highest mean delta C-13 value and mean THg and MMHg concentrations. Differences in SI and Hg data among the three species were attributed to their different trophic functional groups, regional features and relative incidences of species collected at our sampling sites. The determination of baseline THg and MMHg concentrations and insight on how concentrations vary with geographical correlates reported here among three common Arctic decapod species will contribute to closing the Hg-benthos knowledge gaps within the Arctic food web.