The Zebra Mussel is a small freshwater mollusk that is native to the Caspian and Black Sea.  It was first sighted in the United States in 1988 in Lake St. Clair.  Its spread to the United States is believed to be caused by the transfer of water by commercial transatlantic ships.  The first commercial report in Lake Champlain was in 1993.


MAP OF ZEBRA MUSSEL DISTRIBUTION IN 1993

MAP OF ZEBRA MUSSEL DISTRIBUTION IN 1995

MAP OF ZEBRA MUSSEL DISTRIBUTION IN 1997

MAP OF ZEBRA MUSSEL DISTRIBUTION IN 1999