Oyster shells as vectors for exotic organisms

Oyster shell may be taken from one bay and placed in another for a variety of purposes, including the restoration or enhancement of native oysters or other native species. Whereas it is generally appreciated that undesirable organisms can be transferred with live oysters, oyster shells alone can also serve as vectors for the accidental introduction of marine organisms to new locations. We here describe oyster shell plantings made for various purposes, the potential for these plantings to inadvertently transfer live organisms, and biosanitary procedures that could limit these transfers.