Diet influences on growth and mercury concentrations of two salmonid species from lakes in the eastern Canadian Arctic

Diet, age, and growth rate influences on fish mercury concentrations were investigated for Arctic char (Salvelinus alpinus) brook trout fontinalis) in lakes of the eastern Canadian Arctic. We hypothesized that faster-growing have lower because dilution, a process whereby more efficient dilutes fish’s burden. Using datasets 57 133 char, linear regression modelling showed age diet indices dominant explanatory variables muscle both species. Faster-growing (based length-at-age) fed at higher trophic position, as result, their not than slower-growing fish. Muscle RNA/DNA ratios used physiological indicator short-term (days to weeks). Slower inferred from ratios, was found winter versus summer polar desert tundra lakes, but ratio (at best) weak predictor concentration. Net effects concentration greater any potential offset by biomass dilution In these resource-poor faster associated with feeding likely due caloric (and mercury) intake, rather efficiency.