It seems Asian oysters are nearly -- but not quite -- off the menu for restoring Chesapeake Bay's bivalves. 

The natural resources secretaries of Maryland and Virginia conferred by phone today with the commander of the Norfolk District of the Army Corps of Engineers to see if they could come up with a common strategy for rebuilding the bay's battered oyster industry and repopulating the bay with filter-feeding bivalves.  According to all involved, they agreed to focus their efforts on the native oyster, Crassostrea virginica, both for commercial and ecological purposes. 

But some ambiguity remains regarding Crassostrea ariakensis, the Asian oyster.  Col. Dionysios Anninos, the Norfolk Corps commander, said he was drafting a provision to include in the Environmental Impact Statement regarding restoration of the bay's oysters that would "leave that door slightly cracked" to allow for limited, carefully controlled experiments with the non-native bivalve to see if it poses real risks to public health or the environment.

Seafood dealers and watermen have sought approval to raise Asian oysters because they have proven themselves resistant to the diseases that have decimated native bay oysters the past 20 years.  The Asian oysters grow faster and larger than the native species, as shown in the picture above.  But researchers have suggested that Asian oysters also may be more prone to harbor human pathogens, and that they may crowd out native oysters if they breed freely in the bay.  While proponents have said they'd only cultivate oysters genetically modified and bred to be sterile, scientists have said the process is not perfect and would ultimately lead to non-native bivalves breeding in the bay.  Even putting a limited number of sterile oysters in the bay to study them could lead to accidental breeding and spread, critics contend. 

Anninos had wanted to continue studying the Asian oyster on a moderate commercial scale, arguing that several years' worth of "field trials" by Virginia oyster growers had occurred without mishap. The Virginia Seafood Council, representing the state's largest oyster packers, had applied to raise 1.1 million sterile Asian oysters around the bay in another field trial over the next year.  But Virginia officials, who had publicly supported the state's seafood industry untiil now, apparently switched gears and pressured the industry group this week to drop its request. 

Lynda Tran, communications director for Virginia Gov. Tim Kaine, said state officials decided they had to go along with the recommendations of their top scientists at the Virginia Institute of Marine Science, which advised against any more commercial-scale cultivation of the non-native species.  While agreeing to focus the state's restoration efforts on native oysters, Tran said state officials still hoped that "small-scale, tightly controlled scientific studies" might provide additional data to allay fears about Asian oysters' potential to harm people or the bay.  Those findings - and further failures to rebuild native oysters - might reopen the campaign to introduce Asian oysters.

In Maryland, the O'Malley administration has called for a "zero risk" approach to Asian oysters, arguing that state and federal governments should focus their efforts on rebuilding native oyster populations while encouraging watermen and seafood businesses to farm native oysters.   In recent years, some oyster farmers have had success raising disease-resistant strains of the native species, while others have found that native oysters bred to be sterile - like their non-native counterparits - also outgrow the diseases.

Frank Dawson, assistant Maryland natural resources secretary, would not rule out the state agreeing to some kind of experiments with Asian oysters in the bay.  But he suggested that  any "crack" allowing more studies would be carefully reviewed to see if the need for such research was demonstrated, and there were adequate safeguards.

Anninos said he just wanted to keep an option open for more modest studies, with most if not all probably limited to the laboratory to guarantee no oysters accidentally escape into the bay.  He pledged to work with other federal environmental agencies, which have adamantly opposed in-the-wild experiments with Asian oysters, to craft guidelines for any future research. And he said he remained hopeful of achieving a common approach to restoring the bay's oysters.

Reports filtering out about the continuing negotiations left environmental groups unsure whether the state and federal officials were merely going through a face-saving exercise to effectively sideline any further discussion of Asian oysters - or whether the push for more studies was a ruse to avoid a protracted legal and political battle over the use of non-native species in the bay.