Question: how did the zebra mussel problem in the great lakes begin?
Answer: Successful introduction of zebra mussels into the Great Lakes probably occurred in 1985 or 1986, after transoceanic ships discharged contaminated ballast water from foreign ports into lakes St. Clair and Erie. ... Being a temperate, freshwater species, they found the plankton-rich lakes St. Clair and Erie to their liking.