The Japanese oyster, Crassostreas gigas, is an oyster native to the Pacific coast of Asia. It has become an introduced species in North America, Australia, Europe, and New Zealand. The Japanese oyster has spread through accidental introductions either through larvae in ballast water or on the hulls of ships, but is has also been introduced to replace the native oyster stocks which were seriously dwindling due to overfishing or disease. In some places in the world, though, it is considered to be an invasive species. It is large and has rounded, radial folds which are often extremely rough and sharp.
The Swedish researcher Åsa Strand needs your help to report findings of this oyster in Sweden. Send an email to email@example.com with a picture and where you have found it. (Use the Virtue map to find the coordinates)