From the Chesapeake Bay Foundation:

Oysters provide much-needed filtration of Chesapeake Bay waters, habitat for other aquatic life, and a modest commercial harvest. The Chesapeake Bay Foundation estimates the native oyster population to be as low as 4 percent of historic levels. Restoring the Chesapeake’s native oyster population is key to bringing back the Bay’s health.

[Chesapeake Bay Foundation | Via LS]