Changes in mercury bioaccumulation in an apex predator in response to removal of an introduced competitor

摘要: We evaluated methylmercury (MeHg) concentrations in native apex predators, lake trout Salvelinus namaycush before and after the large-scale removal of introduced smallmouth bass Micropterus dolomieu a 270 ha Adirondack lake. Previous studies show that removing competitors can result increased growth decreased mercury remaining fish. Instead, we observed significant increase MeHg despite increases growth. Bioenergetics simulations predicted similar concentrations. Higher prey fish (post-removal diet) relative to invertebrates (pre-removal was most important factor increasing However, this effect counteracted by (i.e., dilution) likely due combination foraging costs an energy density. These data provide evidence for mechanism (diet shift reduced competition) which changes food web structure influence top predators.