Which oysters for the Chesapeake Bay?

Sunday’s Washington Post reports that a decision is expected soon on whether to deliberately introduce the Suminoe oyster, native to China and Japan, to the Chesapeake Bay. A decision would mark the end of an analytic process that has been going on for more than 10 years.

The U.S. Army Corps of Engineers issued a draft EIS last fall considering the impacts of several alternatives, including release of fertile Suminoe oysters and confined aquaculture of sterile oysters.You might wonder why federal agencies are involved at all. Virginia and Maryland proposed the introduction, prodded by the Virginia Seafood Council, which has conducted its own experiments with Asian oysters in tributaries to the Bay.

A Clean Water Act NPDES permit would seem to be required to introduce these organisms into the Bay, but until recently EPA was busy denying that it had any duty to regulate the discharge of living organisms into waterways. The Corps prepared an EIS only because Congress directed it to do so in 2004. Now officials from the Corps, Virginia, and Maryland will decide what to do.

Native oysters have declined drastically, to less than 1% of historic population levels, as a result of overfishing and the spread of parasitic diseases. The value of the Chesapeake Bay oyster harvest dropped by 90% between 198o and 2001. Watermen are understandably concerned that the native oysters may disappear altogether, taking their economic livelihood. But introduction of the Asian oyster does not guarantee improvement.

This is a case where risk assessment and cost-benefit analysis can’t help. The National Research Council concluded in 2004 that it was not possible to quantify either the ecological risks or the economic benefits of introducing Asian oysters. The draft EIS indicates that is still true.

Naturally, views differ about the best course of action. NOAA opposes even the sterile oyster aquaculture option, because

the risks to the Chesapeake Bay ecosystem associated with the proposed introduction of the non-native oyster have not been demonstrated to be acceptably low, and a viable alternative exists which uses only native oysters.

The Chesapeake Bay Foundation agrees.

Support for reintroduction appears to be softening even in Virginia, where Senators this month rejected a resolution of support for the project. Still, the Post reports that Virginia’s natural resources secreaty supports sterile oyster aquaculture. His counterpart in Maryland is said to be skeptical. That would seem to leave the decision in the hands of the head of the local Corps of Engineers office, but it also raises the prospect that Virginia might go ahead without federal approval.

Chesapeake Bay, Clean Water Act, Corps of Engineers, EIS, invasive species, National Research Council, oysters