Cadmium and copper contents in a freshwater fish species (brook trout, Salvelinus fontinalis) from the subantarctic Kerguelen Islands

Abstract : The subantarctic Kerguelen Islands (49 degrees S, 70 degrees E) contain freshwaters among the most isolated in the world from direct human activities. Cadmium and copper concentrations were analyzed in muscle and liver tissues of 57 non-migratory brook trout (Salvelinus fontinalis) inhabiting the Sud River of Kerguelen Islands. The mean cadmium concentration in liver was 1.13 mu g/g dry wt, within the range of levels measured in liver of marine fish from the Southern Ocean. Muscular Cd levels (0.12 mu g/g dry wt) were roughly ten times higher than those measured in Kerguelen's marine fish species. Copper levels were very high in the two organs (62.27 mu g/g dry wt in liver and 3.02 mu g/g dry wt in muscle) compared to those detected in fish from the Southern Ocean. Regarding the seasonal trend, the highest Cu and Cd muscular levels were measured in fish at the end of the austral winter, whereas the highest hepatic levels were observed at the end of the austral summer. Moreover, hepatic cadmium levels were higher in females than in males. These results could be related to brook trout spawning physiological preparations and foraging behavior during the summer period. We provide here the first results about Cu and Cd levels in liver and muscle of a freshwater fish species in an insular subantarctic context. They are in agreement with the high cadmium contamination found in fish of the Southern Ocean