Invasion
Invasion Description
1st Record: NJ/Barnegat Bay (1930s, Andrews 1980, A bushel of oysters was planted but failed to grow, and died within 2 years.). 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 M. 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 ofMC. Ariakensis (Suminoe Oyster), owing to better growth results and higher perceived quality of the latter Asian oyster (Hallerman et al. 2001).
Geographic Extent
West Falmouth/MA/Fresh Pond (Buzzards Bay) (1974-1977, Hickey 1979, spawning observed, no settlement); CT-NY/Long Island Sound (Davis, personal communication, cited by Dean 1979, noted that 'numerous shipments were introduced into Long Island Sound at one time or another'); NJ/Barnegat Bay (1930s, Andrews 1980, A bushel of oysters was planted but failed to grow, and died within 2 years); DE/Rehoboth Bay (1962, held without spawning, Andrews 1980); 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, Calvo et al. 1999); VA/Great Wicomico River (1997, Calvo et al. 1999, planting and recovery of triploids, Calvo et al. 1999); 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)
Vectors
Level | Vector |
---|---|
Probable | Oyster Intentional |
Regional Impacts
Ecological Impact | Parasite/Predator Vector | |
Parasite-Predator vector- Although C. gigas has never become established in the northwest Atlantic, the many failed introductions of C. gigas comprise a likely vector for the introduction of Haplosporidium nelsoni, the cause of the MSX disease which has severely affected the native Eastern Oyster, C. virdinica (Andrews 1980; Burreson and Ford 2004). | ||