Update Of The Issues Surrounding The Introduction Of The Asian Oyster, Crassostrea ariakensis, Into Chesapeake Bay     Frederick G. Kern   NOAA Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, Oxford, MD     Attempts to introduce exotic oysters into Chesapeake Bay are not new.  The pioneer oyster biologist Paul S. Galtsoff reported in 1932 that several unsuccessful attempts had been tried along the East Coast of the United States.  There is good evidence that one of those attempts resulted in the introduction of the parasite Haplosporidium nelsoni, known commonly as MSX.  This parasite has devastated oyster populations along the East Coast of the United States for the last fifty years.  There are a number of examples where the Japanese oyster species, Crassostrea gigas, has become established and has replaced more desirable native oysters.   With the almost complete collapse of the oyster industry in Virginia, researchers have begun water testing of non-native species of oysters under controlled experimental conditions.  The experimental tests were reviewed and approved by an ad hoc panel of the Chesapeake Bay Program.  To prevent the accidental introduction of an exotic species, triploid oysters (presumed to be sterile) were used in each experiment.  There have been three different tests approved over the last five years.  The first involved the use of C. gigas, and the second and third also tested Crassostrea ariakensis, the Chinese Suminoe oyster. These tests revealed evidence of substantial growth of C. ariakensis under varying environmental conditions, and also indicated possible resistance to the oyster diseases common to Chesapeake Bay: MSX and Dermo (Perkinsus marinus).   Little is known about the biology of the Suminoe oyster, so it is impossible to predict the impact on native species in Chesapeake Bay and the East Coast of the United States.  Future testing is being discussed that would greatly expand the number of oysters being placed overboard.  This multifold increase from a few hundred experimental oysters to millions for testing in aquacultural settings has many public and private organizations convinced that a viable population of this new species, C. ariakensis, will become established in Chesapeake Bay and elsewhere along the Atlantic Coast.  Concerns expressed in public hearings will be discussed, as well as the procedures to be used by the ad hoc panel, to evaluate the risk of establishing a new species of oyster in Chesapeake Bay.