Non-native oyster species have been introduced into the U.S. with variable results. The Japanese oyster, Crassostrea gigas , has out-competed and displaced native oysters in the Pacific Northwest, and the European oyster, Ostrea edulis , has gained a foothold in the Northeast, although occupying a different niche than the native oyster population. Other ecological interactions, however, may be less obvious, and yet to be determined. The home aquarium trade and increased interest in garden ponds have greatly increased the importation and culture of exotic ornamental species. Intentional and accidental releases have caused serious problems, especially in southern areas, where tropical species can survive and reproduce.
Many states regulate the importation of living marine organisms.
Permits or licenses are required that allow a review of the proposed activity, site and species for adverse affects and unwanted releases. In most cases, exotic species are not allowed to be grown or maintained where escapes are possible or local populations may be infected. Genetically altered organisms which are sterile may also help to reduce risks, but not eliminate them completely. Policies and regulations need to be updated as new information is discovered. To find out about New England states' programs see policies and regulations.