THE VIRGINIAN-PILOT
Copyright (c) 1996, Landmark Communications, Inc.
DATE: Saturday, August 10, 1996 TAG: 9608100311
SECTION: BUSINESS PAGE: D1 EDITION: FINAL
SOURCE: BY SCOTT HARPER, STAFF WRITER
LENGTH: 74 lines
Researchers have found a potentially dangerous parasite living in Virginia waters - one that has killed hard clams and damaged the lucrative clam industry in New England, the Virginia Institute of Marine Science reported Thursday.
However, the protozoan called Quahog Parasite Unknown, or QPX, has only lightly infected two of 25 hard clams sampled in Chincoteague Bay, near the Maryland line, according to the VIMS study.
And there is some evidence that the clams in this oceanside bay are developing an immunity to the new intruder, researchers said.
Closer to Hampton Roads, QPX was not spotted in clams examined last month in the lower James River or along the Chesapeake Bay on Virginia's Eastern Shore, said senior marine scientist Lisa Calvo, who participated in the state-funded parasite hunt.
``The bad news is that we found it here at all; the good news is that it isn't causing any problems so far,'' Calvo said.
VIMS decided to release its limited research now to calm any consumer anxiety that may swirl around the news of a new seafood parasite, Calvo said.
The institute also wanted to stress that QPX should not be compared to MSX, a different parasite with a similar moniker that is largely responsible for decimating the Chesapeake Bay oyster population.
Neither parasite is harmful to humans if ingested. They are troublesome only to their shellfish hosts, Calvo said.
Hard clams are those sold steamed on the half shell and used in clam chowder; soft clams - those with long, tubular tails - are not affected.
In 1995 in Virginia, 943,748 pounds of wild hard clams were landed at state docks, worth about $4.9 million, according to the Virginia Marine Resources Commission.
An additional 50 million individual hard clams were sold from aquaculture operations across Virginia, netting about $8 million in profits, said Elaine Lidholm, a spokeswoman for the Virginia Department of Agriculture and Consumer Services.
As QPX migrated south from Canada to New England in recent years, Virginia and other coastal states with active clam industries have watched nervously, wondering whether the microscopic critter would soon enter their waters.
In this anxious spirit, Gov. George F. Allen and the General Assembly agreed last year to fund exploratory research. Given its early findings, VIMS intends to expand its survey to include other areas in the lower Chesapeake Bay and on the Eastern Shore, where much of Virginia's clam industry is located.
Little is known about QPX. It is believed to have originated near Prince Edward Island in Canada in 1959. In the early 1990s, hard clams raised in captivity on Cape Cod started to die from QPX infection.
Then last year, in aquaculture farms in Provincetown on Cape Cod and in waters south of Boston, clam growers noticed heavy die-offs in their juvenile stocks, said Jerry Moles, an aquaculture specialist with the Massachusetts Division of Marine Fisheries.
Massachusetts now is getting serious about the problem, which for some reason has not struck wild clams, only human-raised ones, Moles said.
The state plans to hire its own QPX research scientist and will continue to require disease-free certification for clam seed brought into Massachusetts, Moles said.
Similarly, the clams affected in Chincoteague Bay were raised in captivity. Gene Burreson, a VIMS scientist leading the research, said there is some belief that QPX occurs when clams are crowded too close together or become stressed for other reasons, such as a lack of food or poor water quality.
``It appears to be an opportunistic species,'' said Calvo. ``When a clam loses the capacity to fight, that's when it seems to get inside.''
Nationally, the hard clam industry produced 11.5 million tons of meat valued at $40.2 million in 1994, the last year national seafood statistics were available for wild clams only. ILLUSTRATION: Color photo by BILL TIERNAN, The Virginian-Pilot
Clams... by CNB