Complications of a non-native oyster introduction: facilitation of a local parasite

Among the risks of introducing non-native species to novel environments is the possibility that the non-native might serve as a reservoir for enzootic pathogens formerly at low abundance. The recent identification ofBonamiasp. in previously uninfected non-native Suminoe oysters deployed to Bogue Sound, Morehead City, North Carolina, USA, raises serious concerns about the oyster’s ability to act as a reservoir for the parasite, not formerly known along the east coast of the USA. To assess the current distribution of theBonamiasp. parasite and its environmental tolerances, non-reproductive triploid Suminoe oysters, certified as uninfected, were deployed at 5 high salinity sites across North Carolina, chosen because of their similarity to the Bogue Sound site, and along a salinity gradient radiating from Morehead City Port, at which the parasite is known to occur. Screening of 2 oyster cohorts failed to detect theBonamiasp. parasite beyond the immediate vicinity of Morehead City port. At the port, infection was almost entirely confined to small (