TITLE: DEAD CLAMS MYSTIFY RESEARCHERS
BYLINE: LANE DEGREGORY and Scott Harper, Staff writers
EST. PAGES: 2
DATE: 09/20/97
DOCID: NFLK72630396
SOURCE: The Virginian-Pilot and The Ledger-Star, Norfolk, VA; NFLK
EDITION: NORTH CAROLINA; SECTION: LOCAL; PAGE: B1
(Copyright 1997)
COROLLA - Thousands of dead or dying surf clams washed ashore
on this northern Outer Banks beach this week, spread across a
stretch of shoreline as long as 8 miles.
The clams first started showing up on Sunday and were tangled
in mounds of starfish, said Corolla Fire and Rescue volunteer
Tom Musika. They were concentrated in piles every 20 to 30 feet
- with the densest groupings around the Corolla Light water tower
and north of the road's end in Carova. The kill did not extend
to the Virginia line.
By Friday afternoon, birds had eaten many of the clams, and
other shellfish had washed back into the ocean.
But hundreds of the inch-long clams still were strewn along
the sand.
State officials said they'd never heard of such a large amount
of clams washing up along the ocean.
And opinions varied about what might have caused the kills.
On Wednesday and Thursday, fisheries experts collected tissue
and water samples from the clams. Al Hodge, a water quality specialist
with the North Carolina Department of Environment, Health and
Natural Resources, said officials are checking to see if disease
or a deadly microbe, Pfiesteria piscicida, might have been the
culprit. The tests are "just a precaution," Hodge said
Friday - noting that the shellfish showed no lesions or other
signs of a pfiesteria attack.
Another theory is that rough waters stirred up by Hurricane
Erika along the Outer Banks might have killed the clams. Hugh
Porter, curator of the wildlife collection at the University of
North Carolina's Institute of Marine Sciences in Morehead City,
said high waves churn up a lot of sand along the shore.
"If the clams get filled up with large amounts of sediment,
they can't expel that," he said Friday.
"Clams are filter feeders. And they can't clean the sand
out," Porter said. "They get packed with sediment and
can't survive.
"Surf clams normally burrow an inch or so into the sand
below the ocean. If they start dying, they lose their ability
to burrow. Then they end up on the surface of the sand and stand
a greater chance of being washed ashore."
Surf clams grow up to 6 inches across and live along the Atlantic
from Nova Scotia through Cape Hatteras. Porter said he has heard
of droves of the edible shellfish washing ashore along the New
Jersey coast - "especially after storms that have a lot of
wave action." But the Corolla case is the first time he's
heard of that happening in North Carolina.
"This probably is not a disease-caused phenomenon,"
he said. "But you can never be sure."
Pfiesteria, a one-celled predator, is suspected in the deaths
of a billion fish in North Carolina and thousands of others in
three waterways in Maryland and Virginia. Those kills all occurred
in inland waters. The microorganism has not been found in its
toxic form in the ocean.
Some citizens theorized that a "red tide" of toxic
algae might have killed the clams. But the ocean off Corolla showed
no discoloration Thursday, Hodge said. And he did not think a
shock of pollution was to blame.
"Something came through here," Hodge said. "There's
no telling what it was."
If the hurricane did cause the clam kill, Hodge wondered, why
didn't more clams show up elsewhere on the Outer Banks?
ART: Color photo DREW C. WILSON/The Virginian-Pilot
Vacationer Gene Glave of Isle of Palms, S.C., holds washed-up surf
clams Friday at Corolla.
DESCRIPTORS: CLAM KILL; OUTER BANKS