Ecotoxicology

, Volume 18, Issue 5, pp 488–498

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

  • Jesse M. Lepak
  • Jason M. Robinson
  • Clifford E. Kraft
  • Daniel C. Josephson
Article

DOI: 10.1007/s10646-009-0306-5

Cite this article as:
Lepak, J.M., Robinson, J.M., Kraft, C.E. et al. Ecotoxicology (2009) 18: 488. doi:10.1007/s10646-009-0306-5

Abstract

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

Keywords

MercuryFood webFish removalGrowth dilutionLake troutSmallmouth bass

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Jesse M. Lepak
    • 1
  • Jason M. Robinson
    • 2
  • Clifford E. Kraft
    • 2
  • Daniel C. Josephson
    • 2
  1. 1.Warner College of Natural Resources, Colorado Cooperative Fish & Wildlife Research UnitColorado State UniversityFort CollinsUSA
  2. 2.Department of Natural ResourcesCornell UniversityIthacaUSA