Disease and overfishing have so depleted Chesapeake Bay's oysters that the only way of restoring the once-abundant shellfish may be to ban catching them for several years, says a Virginia marine scientist.
William J. Hargis Jr., former director of the Virginia Institute of Marine Science and a long-time oyster researcher, warned the Chesapeake Bay Commission yesterday that unless Maryland and Virginia drastically change their current policies, "sooner or later the oyster industry will just go down."
Maryland officials attending the commission's meeting at the Conowingo Dam in Harford County quickly rejected the proposal for a moratorium.
Natural Resources Secretary Torrey C. Brown said he doubted that oysters would revive if just left alone.
But William C. Baker, president of the Chesapeake Bay Foundation, said the Annapolis-based environmental group was so alarmed by the oyster's decline that it was considering calling for a three-year ban on commercial harvests.
The mainstay of the bay's seafood industry a century ago, oysters have been badly battered by overharvesting and by two parasites, MSX and Dermo, which invaded the bay nearly 30 years ago.
Virginia's oyster harvest last year was just 161,000 bushels, down from annual oyster landings of 2 million to 3 million bushels from 1930 until 1965, when MSX first ravaged that state's waters. The peak catch topped 7 million bushels in 1904.
Maryland oyster harvests have not plunged as low, Hargis said, largely because the MSX parasite has retreated from the fresher northern bay waters in the past three years.
But he warned that Maryland's much-diminished oyster industry also will be on the brink of collapse in two to four years unless state fishery policies are changed.
Maryland's oyster harvest actually increased this year to 415,000 bushels, up nearly 10 percent from last year's take, according to W. Peter Jensen, tidal fisheries director for the state Department of Natural Resources.
But future harvests are likely to drop again because oyster reproduction in the past two years has been very poor, said George Krantz, director of the federal-state cooperative biological laboratory at Oxford.
And while the MSX parasite has largely vanished from Maryland waters after killing off 75 to 100 percent of the oysters it infected four years ago, Krantz said, the other parasite, Dermo, has spread throughout the bay and has wiped out 25 to 50 percent or more of the oysters in some areas.
Overharvesting in Virginia waters has intensified since the latest MSX outbreak in 1986, Hargis said.
Virginia watermen pressured that state to allow harvesting from disease-free oyster beds in the James River. But those beds are the source of all of Virginia's seed, or young, oysters, Hargis said, so that taking those has undercut reproduction.
One of the major causes of the oyster's long-term decline throughout the bay, Hargis said, has been the deterioration and destruction of many of the underwater reefs on which shellfish grow.
In colonial days, oyster bars were so near the surface that mariners feared sinking their ships if they sailed over them, Hargis said. But dredging, storms and decades of raking them over in search of oysters have worn many reefs down to where they are no longer suitable habitat.
Hargis urged fisheries officials to cut back on the harvest pressures on oysters by refusing to issue new licenses to watermen and by raising licensing fees.
He also urged the states to restore the lost reefs. The bay foundation is considering recommending that watermen be paid during an oyster moratorium to help rebuild the bars, which Hargis termed a reasonable idea.
Baker said that foundation scientists were concerned because the oysters being harvested now were the ones most resistant to disease, so that the bay was being robbed of its hardiest brood stock.
Though some argue that the key to reviving the bay's oyster industry is aquaculture, Hargis said, "Nature can outproduce anything we can do in a hatchery."
If the states are unwilling to ban oyster harvests baywide, Hargis urged them at least to set aside some reefs as oyster sanctuaries, which would not be reopened even after they were restored. He also called for encouraging more planting of oysters on privately owned or leased reefs.
Hargis predicted that the oyster industry could be on its way to recovery in three to five years if his recommendations are tried. But he added that "if something isn't done, the game's over."
Brown, Maryland's natural resources secretary, acknowledged that "we need to do something," but he contended that a moratorium "won't work."
In Maryland, 80 percent to 90 percent of the 283,000 acres of oyster bars already are under a de facto moratorium, Brown said, because watermen work only 10 to 20 percent of the bottom in any year. Those unharvested areas have not bounced back, he noted.
Maryland officials are looking at the feasibility of rebuilding oyster reefs, Brown said. Half or more of the oyster bars that NTC existed in the early 1900s have been obliterated since then.
Krantz, DNR's leading oyster scientist, did not say whether he favored imposing a moratorium on harvests. But he said that his research had raised serious questions about the likely success of proposals to import West Coast oysters to revive the bay's seafood industry.
West Coast, or Japanese, oysters are far less susceptible to the parasites ravaging the native Chesapeake oysters, Krantz said, but most of the imported oysters tested in DNR's Deal Island hatchery died anyway.
And West Coast oysters seem susceptible to carrying other bacteria, diseases or parasites that might further infect the Chesapeake's native stock if the imports are placed in the bay, Krantz said.