Crassostrea virginica (C. virginica)
Common names: Eastern oyster, Atlantic oyster, Gulf oyster, Blue Point, Malpeque
This is the great American oyster, the species that occurs naturally from Canada down the East Coast to New York and Chesapeake Bay and all the way across the Gulf.
Crassostrea gigas (C. gigas)
Common names: Pacific oyster, Japanese oyster, creuse (France)
Introduced to the Pacific coast from Asia in the early 20th century and the French coast in the 1970s, C. gigas is the most common farm-raised oyster in the Pacific Northwest and France.
Crassostrea sikamea (C. sikamea)
Common name: Kumamoto
This oversized thimble of an oyster is farm-raised in the Pacific Northwest. It has a deep bottom shell and a fluted lip. It was introduced to Washington from Kumamoto Prefecture in southern Japan in 1947.
Ostrea conchaphila (O. conchaphila) or Ostrea lurida (O. lurida)
Common names: Olympia oyster, Oly, tiny Pacific oyster
Early taxonomists thought these were two different species, but in the 1990s, scientists agreed they were identical and combined the two names. About the size of a 50-cent piece, the tiny Olympia is the indigenous oyster of the Pacific Northwest. Like the European flat, it is a member of the genus Ostrea. The Olympia fishery collapsed in the late 19th century, but the oyster has been revived in recent years, thanks to the efforts of dedicated oystermen and environmentalists.
Ostrea edulis (O. edulis)
Common names: European oysters, flat oysters, Belons
This is the oyster of the Roman orgy and the French Renaissance. The shallow, round shell resembles a dinner plate, hence the "flat" name. The flavor is the boldest in the oyster world, with strong marine components and an intense mineral aftertaste. After centuries of overfishing and the ravages of oyster diseases, O. edulis is on the verge of disappearing.
More info on where to eat oysters in S.F and what species to look for.
Oyster Lovers Unite
This Valentines weekend may be your best chance to eat oysters for years to come.