Great Lakes Institute for Environmental Research, University of Windsor,Windsor, ON, N9B 3P4, Canada
^†Current Address: Biology Department, Lakehead University, Thunder Bay, ON, P7B 5E1, Canada

*Corresponding author

Summary

   Lake Erie has an extensive history of human-mediated perturbation, ranging from habitat destruction to nutrient and contaminant loadings and introduction of nonindigenous species (NIS). Currently, at least 72 NIS of aquatic vertebrate and invertebrate animals, protists, algae and submerged macrophytes are established in Lake Erie. Fishes and algae are represented by the most NIS (16 species each), followed by molluscs (13 species), crustaceans (10 species) and submerged macrophytes (7 species). In addition, 10 NIS of protists, bryozoans, hydrozoans and insects are established in the lake. Both the taxonomic composition of new NIS and pathway of introduction have varied temporally. Before 1880, aquatic invaders consisted primarily of fishes that were deliberately introduced. Molluscs were the principal invaders between 1881 and 1920, and were introduced by a variety of mechanisms including ships’ solid ballast and aquarium releases. After 1920, a wide variety of aquatic NIS were introduced via an array of vectors, although ballast water was the predominant pathway (responsible for 66% of invasions after 1960). NIS continue to establish in Lake Erie at a rate of one invader per year; and until the numerous pathways of introduction are addressed, it is expected that the lake remains at risk of further invasion.