Low concentrations of contaminants in an invasive cyprinid, the rudd, in a Great Lakes Area of Concern.

Abstract

The invasive, omnivorous rudd Scardinius erythrophthalmus is abundant in the upper Niagara River, a Great Lakes Area of Concern. Invasive species can alter trophic and contaminant pathways, but complex ontogenetic and seasonal diet shifts by rudds make it difficult to predict their chemical burdens relative to other fishes. We quantified concentrations of chemical residues in rudds and compared them to six fish species from various trophic levels. Rudds contained low concentrations of total dichlorodiphenyltrichloroethane (mean=0.02μg/g), Hg (mean=0.03μg/g), and polychlorinated biphenyls (mean=0.06μg/g); these concentrations were among the lowest for all species examined. Concentrations of aldrin, heptachlor, hexachlorobenzene, total hexachlorocyclohexanes, mirex, and total chlordanes were less than the method detection limit for all rudds examined. If reducing rudd biomass is determined to be beneficial, resource managers could consider targeted harvest, given the low concentrations of contaminant in rudds and their susceptibility to capture.