MERCURY ACCUMULATION IN ARCTIC CHAR {SALVELINUS ALPINUS) AND BROWN TROUT (SALMO TRUTTA) IN AN ACIDIFIED COASTAL AREA, S.W. NORWAY
Muscle mercury accumulation in Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) have been studied in two small acidified coastal watersheds in S.W. Norway. Individual mercury concentration varied between 0.05 and 0.31 ppm (ìg/g) Hg, and increased significantly with age in all fish stocks, except one. Brown trout from Lake Djupvikvatn had the highest rate of mercury accumulation with age. Based on water chemistry and fish population responses this lake apparently is most severely affected by acidification. Further, Arctic char and brown trout from Lake Selura had a lower mercury concentration (adjusted to the same age) compared to conspecifics from the upstream and more acidified Lake Skogevatn. Our results indicate that the process of acidification may increase mercury accumulation in fish. No significant differences in mercury accumulation was found between sympatric stocks of Arctic char and brown trout.