The Great Lakes have been invaded by at least 140 species, many of which now dominate production and biomass. Ponto-Caspian species enter the Great Lakes directly via ports on the Black and Azov Seas, or indirectly from other European ports that have been previously invaded. The water flea Cercopagis pengoi , the most recent addition to the Great Lakes fauna, was first observed during summer 1998 in Lake Ontario, though it has since spread to the Finger Lakes in New York, and to Lake Michigan. Bythotrephes , a related zooplankton which invaded from the Baltic Sea region during the 1980's, is now found in 39 inland lakes around the Great Lakes. We developed a model to predict Bythotrephes occurrence in European lakes, and then applied the model to predict occurrence in North America.
Results indicate that many additional lakes are vulnerable to invasion.
Our work indicates that humans serve as vectors for many acquatic species introductions, and that activities responsible for these invasions must be curtailed to prevent many more invasions by Eurasian species. More generally, we may utilize patterns of species invasions in the Great Lakes and western Europe to critically explore species invasions theory.