Oysters at heart of bay debate

Non-native species attracts industry, might pose threat

January 04, 2002|By Joel McCord | Joel McCord,SUN STAFF

They're meaty and smooth and just a little off-white in color. They aren't prey to the diseases that have ravaged the Chesapeake Bay oyster, and to hear some folks tell it, they taste just as good as the local variety.

They are Crassostrea ariakensis, the Asian cousin of the native oyster, and they were at the center of a debate yesterday in Annapolis over whether they should be introduced into Chesapeake Bay to rescue a foundering oyster industry.

Encouraged by carefully controlled experiments in Virginia's bay tributaries and on its Atlantic coast indicating the Asian oysters grow faster and are hardier than the native bivalves, Virginia's seafood industry is expected to seek that state's approval soon to increase the number being tested in bay waters from 60,000 to 1 million.

"If we don't take a risk and move on these oysters that will survive in this Chesapeake Bay, then we'll lose the oyster industry that's there," Lake Cowart, a Virginia seafood processor, told the Chesapeake Bay Commission yesterday.

But Maryland officials, environmentalists and some bay scientists fear introducing a non-native species could upset the Chesapeake's ecological balance. They argue for more rigorous research.

Jack Travelstead, Virginia's top fisheries regulator, said he expects a request "within the next six months" from the Virginia Seafood Council for permission to expand its testing program. His agency, the Virginia Marine Resources Commission, would hold hearings before deciding.

Maryland officials, who have no say in the matter, have objected to open bay testing. It is unclear if federal agencies have jurisdiction to review Virginia's decision.

Yesterday, the multistate legislative advisory commission heard from scientists, seafood processors and watermen from both states, then adjourned to an Irish pub nearby for a taste testing. The local oyster, Crassostrea virginica, won by a two-to-one margin.

Native to Asia

Researchers at the Virginia Institute of Marine Sciences have been experimenting since 1997 with non-native oysters, genetically altered so they couldn't reproduce. Ariakensis, which is native to China and southeast Asia, thrived.

The oysters grew faster and were all but impervious to Dermo and MSX, the diseases that have done so much damage to the local oysters but don't affect humans.

Oysters, an integral part of the bay's seafood industry, also are important to its health. They filter pollutants, improving water clarity and allowing the light that is crucial to underwater vegetation to penetrate. Their reefs provide habitat for fish and shellfish.

Oyster restoration is near the center of the updated bay cleanup agreement signed in 2000 by leaders of Maryland, Virginia, Pennsylvania, the District of Columbia and the federal government. The agreement calls for a "tenfold increase in native oysters" in the bay by 2010.

Oysters once were so plentiful that their harvests were measured in the millions of bushels. But the population has dropped to 1 percent of historic levels, killed off by pollution, overfishing and, most recently, diseases.

Virginia's harvest during the past season was 20,000 bushels, the lowest ever. Fisheries managers in Maryland predicted this week that the state's 2001-2002 harvest will be only half the 347,968 bushels of last year because Dermo has worsened in the upper bay.

The disease has taken hold even in the Chester River, which had been relatively disease-free the past 25 years, according to Chris Judy, director of shellfish programs at Maryland's Department of Natural Resources.

That's another reason to move ahead on the ariakensis experiments, Larry Simns, president of the Maryland Watermen's Association, told the commission.

"We need to recognize that in other countries, the only way they have an oyster industry is that they introduced non-native oysters," he said. "We don't want to take the risk of not doing something."

But the prospect of expanded testing has raised the hackles of federal agencies and the Chesapeake Bay Foundation.

The Annapolis-based environmental group called for more testing and evaluation before decisions are made on commercial aquaculture using the Asian oysters. Federal agencies, operating under the umbrella Chesapeake Bay Program, have taken a similar stance, also worrying that even spending money for research on ariakensis would detract from efforts to restore the native oyster population.

"If we send the signal we're looking at something else, it could have an impact on our ability to get funds, public and private," for native oyster restoration, Carin Bisland, of the bay program, told the commission.

A delicate balance

Non-native species introduced by accident or for hunting and trapping purposes over the years have altered the bay's delicate ecological balance, often edging out native species.

The research done to date on ariakensis shows that it is "attractive to industry," said Rob Brumbaugh, a bay foundation scientist. "But we don't know the answers to other questions."

For example, he asks: Can the native oyster survive in the same waters with the Asian oyster? Will the other oysters bring diseases no one knows about?

Even the Virginia scientists are leery of letting non-native oysters loose in the bay, regardless of whether they've been sterilized.

"The environments are so complex, you can't predict what might happen," said Gene Burreson, part of the VIMS team. "It could introduce another disease, it could displace the native oyster. There are things you can't predict. One thing we've learned worldwide is it's a real crap-shoot to introduce a non-native species, and it could be real bad."

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