Ecotoxicology of mercury concentrations in arctic lamprey (Lethenteron camtschaticum)

Arctic lamprey (Lethenteron camtschaticum) is an important dietary resource for rural and indigenous communities in parts of Alaska, with some commercial use. As with many fish species harvested for human consumption, there are concerns regarding mercury concentrations ([Hg]) in Arctic lamprey that may impact human health. To date, information regarding the life cycle and diet of Arctic lamprey is scarce, with no published studies examining [Hg] in Arctic lamprey tissues. Our goals were to investigate the feeding ecology of Arctic lamprey from the Bering Sea, determine how diet and potential dietary shifts might influence [Hg] in muscle, and determine if current [Hg] may pose a human health risk. The mean total [Hg] in Arctic lamprey muscle (n = 98) was 19 ng/g wet-weight. Log transformed total [Hg] were not associated with any measured biological variables including length, mass, δ¹³C values, or δ¹⁵N values. A stable isotope mixing model estimated that capelin (Mallotus villosus) accounted for 40.0 ± 4.0% of the Arctic lamprey diet, while Pacific sand lance (Ammodytes hexapterus) and Pacific herring (Clupea pallasii) accounted for 37.8 ± 3.1% and 22.2 ± 3.5% respectively. Finally, diet percentage compositions shifted based on size class (i.e., medium versus large). These results indicated that feeding location, bioaccumulation, and biomagnification are not important drivers of [Hg] in Arctic lamprey and current [Hg] do not pose a human health risk. Taken together, this research further expands our knowledge of Arctic lamprey trophic ecology in the eastern Bering Sea.