Mercury in Barents Sea fish in the Arctic polar night: Species and spatial comparison.

Although mercury (Hg) in polar ecosystems has been well-studied, there is little information on Hg in the Arctic during low-productivity seasons like the polar night. We quantified Hg concentrations, carbon, and nitrogen stable isotope ratios (δC and δN) in the muscle of polar cod (Boreogadus saida), Atlantic cod (Gadus morhua), and capelin (Mallotus villosus) sampled from the North-West and North-East Barents Sea during November-December 2019. Hg concentrations varied between species (14-175 ng/g dw), dependent on region, but were well below the toxicity threshold for fish health and the EU-accepted threshold for human consumption.