when did zebra mussels come to north america
Zebra mussel They were first detected in Canada in the Great Lakes in 1988, in Lake St. Clair, located east/northeast of Detroit and Windsor.[26] It is believed they were inadvertently introduced into the lakes in the ballast water of ocean-going ships traversing the St. Lawrence Seaway. Another possible, often neglected, mode of introduction is on anchors and chains, although this has not been proven. Since adult zebra mussels can survive out of water for several days or weeks if the temperature is low and humidity is high, chain lockers provide temporary refuge for clusters of adult mussels that could easily be released when transoceanic ships drop anchor in freshwater ports. They have become an invasive species in North America, and as such they are the target of federal policy to control them, for instance in the National Invasive Species Act (1996).