The St Lawrence Seaway opened the Great Lakes to international maritime trade in 1959. Since then the number of invasive species has risen, causing native fish populations to be displaced and food chains disrupted.

American scientists have linked impacts of invasive species to economic indicators for sport and commercial fishing, wildlife viewing, and use of water. According to the the Universities of Notre Dame and Wyoming study, annual loss to sport fishing alone is more than $123 million.

The study says 57 of the 84 invasive spices were transported to the Great Lakes in ballast water of ships. A number of regulations are already in place for handling ballast water but discrepancies between Canadian and U.S. requirements makes monitoring difficult.