Asterias amurensis, also known as the Northern Pacific seastar and Japanese common starfish, is a seastar native to the coasts of northern China, Korea, Russia and Japan. This species has been introduced to the oceanic areas of Tasmania, southern Australia, Alaska, the Aleutian Islands, parts of Europe, and Maine. Based on the distribution of northern Pacific seastar populations in shipping ports and routes, the most likely mechanism of introduction is the transport of free-swimming larvae in ballast water for ships. The ships suck in the ballast water containing seastar larvae, in a port such as one in Japan, and let it out in a port such as one in Tasmania, the larvae come out with the water, and metamorphose into juvenile sea stars.