In conjunction with warming temperatures and sea ice reductions, there has been a shift from arctic to subarctic forage fish over the past two decades within the eastern Canadian Arctic. Subarctic capelin (Mallotus villosus), (Ammodytidae) and/or herring (Clupea harengus) are now common in the low Arctic, and may be replacing arctic cod (Boreogadus saida). This change has, so far, occurred to a lesser extent in the mid-Arctic, and only very recently have Inuit observations of capelin been made in the high Arctic. These small fish are eaten by larger fish, seabirds, seals and whales. This project assesses contaminant levels in these fish and other invertebrate prey that comprise the diet of an important NCP monitoring species, ringed seal. Contaminant levels are compared among prey species and among three NCP "focal" ecosystems exhibiting differential extents of forage fish changes, specifically, Hudson Bay (low Arctic, Arviat), Cumberland Sound/Davis Strait (mid-Arctic, Clyde River) and Barrow Strait/Lancaster Sound (high Arctic, Resolute). Ancillary data including fish length, lipid content, fatty acid signatures, selenium concentrations, and nitrogen and carbon stable isotope ratios are being used to, e.g., interpret interspecific and regional variation in contaminant levels.