Mercury Contamination in the Fishes of Glacier National Parl

Abstract

We investigated mercury contamination in fishes from four lakes in Glacier National Park. Three of these lakes (Bowman, Harrison, McDonald) are on the west side of the park, and one is on the east side (St Marys). We focused our sampling on lake trout (Salvelinus namaycush) but also collected lake whitefish (Coregonus clupeajormis), burbot (Lota Iota), and incidentally killed bull trout (Salvelinus confluentus). Mercury contamination generally increased with fish size but not always. Lake trout and burbot were the most contaminated species and levels exceeding 0.5 ppm Hg wet occurred in the larger fish. We found that lake whitefish and bull trout generally had lower mercury levels than lake trout on a size normalized basis. Examination of the lake trout and lake whitefish data revealed that males and females had similar levels of mercury. Mercury levels in lake trout from the west side lakes showed similar trends with fish size, and were comparable to other lake trout populations in the region.