Invasion

Invasion Description

1st Record: MD/"Maryland waters' ('recently, ~1980; Andrews 1980, removed by divers) A number of illegal and government plantings were made from Cape Cod to Chesapeake Bay from the 1930s to 1980s, but settlement of larvae and establishment of Pacific Oysters was not observed (Andrews 1980). Controlled, experimental plantings of sterile, triploid C. gigas in Virginia waters showed that these oysters were disease resistant, but grew poorly at low salinity sites. After 1998, further trials with M. gigas were suspended, in favor of M. ariakensis (Suminoe Oyster), owing to better growth results and higher perceived quality of the latter Asian oyster (Hallerman et al. 2001).

Geographic Extent

MD/'Maryland waters' ('recently, ~1980; Andrews 1980, removed by divers); Gloucester Point/VA/York River (1993, experimental planting of triploid oysters, removed when some reversion to diploid status was observed, Mann and Burreson 1994); VA/Coan River, Potomac tributary (1997, Calvo et al. 1999, planting and recovery of triploids); VA/Great Wicomico River (1997, Calvo et al. 1999, planting and recovery of triploids); VA/Corrotoman River, Rappahannock tributary (1997, Calvo et al. 1999, planting and recovery of triploids); VA/Woodas Creek, Mobjack Bay (1997, Calvo et al. 1999, planting and recovery of triploids); Gloucester Point/VA/York River (1997, Calvo et al. 1999, planting and recovery of triploids); Accomack County/VA/Nandua Creek (1997, Calvo et al. 1999, planting and recovery of triploids); Fisherman's Island/VA/Chesapeake Bay-Atlantic Ocean (1997, Calvo et al. 1999, planting and recovery of triploids)