http://www.nature.com/articles/srep34057
A group of Taiwanese scientists published their findings on the origin of Oysters on Nature’s Scientific Reports.
The Pacific cupped oyster grows much larger than the Portuguese oyster. The two cannot reproduce with each other.
The most common commercial oyster is the Pacific cupped oyster, Crassostrea gigas, which is indigenous to Japan. It’s cultivation has been popularized to the entire world, and it’s usually what we get when we order oysters around the world.
For years, due to geographic proximity to Japan, scientists just assumed Taiwan’s oyster also falls into the Pacific cupped oyster category. This newest study points out that not only is Taiwan’s oyster not the Pacific cupped oyster, Taiwan is the likely origin for the Portuguese oyster, C. angulata.
In the 1960s, commercial oysters in Europe, all Portuguese oyster, suffered a catastrophic calamity, where an infection wiped out all European commercial oysters. Europeans later replaced all commercial oysters with Japan’s Pacific cupped oyster. At the same time, Taiwan’s oysters also suffered from the same infection, but there was enough diversity within the group so that most of them survived.
There’s more diversity within Taiwan’s “Portuguese oyster” group than one would find in China’s “Portuguese oyster” group. Pointing to Taiwan as the likely origin of “Portuguese oysters”.
It also means that commercial cultivated Portuguese oyster in Europe before 1960 was introduced by the Portuguese to Europe after the age of discovery.