The European green crab (Carcinus maenas) was accidentally introduced to the Western Hemisphere in the early 1800s. It is believed that the crab larvae arrived in the United States in wooden shipping crates or barrels of ballast water from Europe, possibly from the port of Plymouth, England, and by 1817 it had become established in the waters of the northwestern Atlantic. The crab's ability to adapt quickly to new environments, combined with its voracious appetite and competitive nature, enabled it to spread rapidly along the Atlantic coast. From there, it gradually made its way to the Pacific Ocean via man-made canals and has now become an invasive species along both the Atlantic and Pacific coasts of North America.