WILLIAMSBURG, Va. -- Faced with an oyster debacle in the Chesapeake Bay, Maryland and Virginia must act boldly to revive the moribund shellfish population.
Leading marine scientists delivered that message to the Chesapeake Bay Commission at a meeting here last week and said that neither state can afford to stand pat.
Oyster harvests have hit an all-time low and the population has been decimated by the parasites MSX and Dermo, which kill oysters before they reach marketable size but are harmless to humans.
Summoned before the commission on Thursday, the panel of scientists from Maryland and Virginia said this spring's heavy rains could give oysters a respite from the parasitic diseases.
But both states must expand their efforts to restore the vast acreage of oyster reefs worn down by watermen or buried by silt over the past century, the panel said.
In briefing the commission of legislators from Maryland, Virginia and Pennsylvania, the scientists recommended:
* Adopting new restrictions on oystering, to prevent watermen from picking clean the few oyster beds not depleted by MSX and Dermo.
* Turning some rivers and coves into permanent sanctuaries, off limits to tongers, dredgers and divers.
* Doing more to encourage oyster aquaculture by entrepreneurs in waters leased from the government.
On the panel were: Dr. William J. Hargis, of the Virginia Institute of Marine Science (VIMS); Dr. Eugene Burreson, also from VIMS; Dr. Roger I. E. Newell, of the University of Maryland's Horn Point Environmental Laboratory near Cambridge; and Dr. George E. Krantz, of Maryland's Cooperative Biological Laboratory in Oxford.
They differed over whether the oyster would ever return to the abundance of old.
Dr. Hargis said that intelligent regulation of harvesting could revive the population. But his Virginia colleague disagreed.
"Managing around the diseases will never get us back to where we were 50 years ago," said Dr. Burreson. "We need disease-resistant oysters."
Only about 300,000 bushels of oysters were harvested last fall and winter in Maryland, Virginia and the Potomac River. That is about one-tenth the harvest of a decade ago.
Prompted by the bleak outlook for the once-thriving industry, Maryland and Virginia plan to review their oyster-management strategies.
Maryland's Department of Natural Resources is organizing an oyster "summit" this summer to be attended by scientists, watermen, environmentalists and representatives of the seafood industry.
Every possible solution will be considered, from a total moratorium on harvesting to rebuilding reefs to expanding disease research, said W. P. "Pete" Jensen, state director of tidal fisheries.
In Maryland waters alone, at least 80,000 acres of once-productive oyster reefs have been lost in the past 80 years, leaving about 120,000 acres of bottom suitable for shellfish, Mr. Jensen said.
The state plans to build eight artificial reefs of old tires, cement or other hard material, to give oyster larvae a place to attach and grow.
With its oyster harvest even more depressed than Maryland's, Virginia is abandoning its old approach to shellfish management: seeding beds with shell and baby oysters.
The state plans to create reefs in the James and Piankatank rivers, to see whether oysters can better withstand diseases by being raised off the bottom. Those and other oyster grounds rehabilitated by the state will be set aside as sanctuaries, said Erik J. Barth, deputy fisheries manager for the Virginia Marine Resources Commission.
In another first, Virginia plans to close public oyster grounds when watermen have taken 50 percent of the shellfish that could be legally harvested there.
Maryland's Dr. Newell said both states need to go beyond aiding the public oyster fishery and should "allow aquaculture to flourish."
He said that Maryland, in particular, should remove legal restrictions on leasing open water, for raising oysters in floating trays or bags. And both states should make some once-productive oyster beds available to private growers, he said.
Maryland and Virginia now lease only bay bottom where oysters never have been found before.
Dr. Newell pointed out that the oyster's decline has worsened the Chesapeake's pollution problem, because shellfish filter out nutrients fouling the water.
The states' oyster-management efforts to date have focused on helping the seafood industry rather than on restoring the oyster's ecological role, said Maryland Sen. Gerald W. Winegrad, D-Anne Arundel, a bay commission member. "That type of management has to stop," he said.
The scientists warned that MSX and Dermo will always threaten the oyster's long-term recovery, because the parasites spread and kill when water conditions are best for shellfish growth and reproduction.
"These ideas are beautiful about making reefs or sanctuaries, but disease will compromise their effectiveness," said Maryland's Dr. Krantz.
For that reason, Virginia scientists have revived their controversial proposal to test Japanese oysters in the bay. Trays holding about 600 of the non-native shellfish would be placed in the York River for about 14 months starting this summer to see if the oysters succumb to parasitic diseases.
Laboratory studies indicate that Japanese oysters, which are grown commercially on the West Coast, do not die from Dermo. But researchers have been unable to test the oyster's resistance to MSX, since that parasite cannot be grown or transmitted in the laboratory.
The Virginia experiment was shelved last summer after Maryland officials objected, saying they feared that Japanese oysters might introduce diseases or reproduce in the wild and crowd out native oysters.
To ease those fears, Virginia scientists have modified their plans. The experimental oysters have been chemically sterilized, and each has been checked to make sure it cannot spawn. Moreover, these shellfish are the fourth generation to be spawned and raised in a hatchery, long enough to guard against the appearance of any new diseases or parasites.
"There's not ever 100 percent certainty in a biological system," said Dr. Dennis L. Taylor, director of VIMS. But he added, "I think we're at a level where the probability [of mishap] is so infinitesimally small that we're unlikely to have a problem."
'An enormous risk'
Maryland fisheries officials are reviewing the plan and expect to respond within a couple of weeks, said Mr. Jensen.
"We still think it's an enormous risk," he said. But he added that "we're willing to take a positive look at this proposal, and if our concerns have been met we will cooperate."
However, William J. Goldsborough, fisheries scientist for the Chesapeake Bay Foundation, said officials should decide whether they will permit Japanese oysters to be produced in the bay before letting the experiment go forward.
"Before opening the hornet's nest, [Virginia should] have it all
mapped out," said Mr. Goldsborough.