 C. maenas was first observed on the east coast of North America in Massachusetts in 1817 , and may now be found from South Carolina northwards ; by 2007 , this species had extended its range northwards to Placentia Bay , Newfoundland . In 1989 , the species was found in San Francisco Bay , California , on the Pacific coast of the United States . Until 1993 , it was not able to extend its range , but reached Oregon in 1997 , the state of Washington in 1998 and British Columbia in 1999 , thus extending its range by 750 kilometres ( 470 mi ) in ten years . By 2003 , C. maenas had extended to South America with specimens discovered in Patagonia . 
