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Jul 16, 2010 9:37 AM by Sharlee Barriere

Widespread Oyster Deaths Found on La. Reef

NEW ORLEANS (AP) - Surveys of coastal oyster grounds have
discovered extensive deaths of the shellfish, further threatening
an industry already in free-fall because of BP's oil spill in the
Gulf of Mexico.
The deaths are blamed on the opening of release valves on the
Mississippi River in an attempt to use fresh water to flush oil out
to sea. Giant diversion structures at Caernarvon and Davis Pond
have been running full-tilt since May 8 on the orders of Louisiana
Gov. Bobby Jindal.
More than 34,550 cubic feet of water per second is flowing into
coastal Louisiana, enough to fill the Superdome once an hour.
"What I saw does not look good," Patrick Banks, oyster manager
for the Louisiana Department of Wildlife and Fisheries, said in an
e-mail. He said he found no evidence of oil on the reefs east of
the Mississippi River, but he said they "looked to be fallow
reef."
Banks dove onto reefs at Black Bay, Bay Crab and Telegraph
Island, where the state is building public oyster grounds for
farmers to collect baby oysters and transfer them to their private
leases. Once there, they are raised to market size.
Public reefs account for up to half of Louisiana's oyster
harvest, an industry that employs about 6,000 people and is valued
at $330 million.
On Thursday, Banks said oyster deaths also were found west of
the Mississippi, though the surveys there are not yet complete.
Reports also are coming in about damage to private oyster
grounds.
John Tesvich, chairman of the Louisiana Oyster Task Force, a
state committee overseeing the industry, said the reports of oyster
deaths on private leases are worrisome.
Oysters use salt water to make their shells and need it to keep
their vital membranes working properly. They can tolerate small
doses of fresh water for perhaps a couple of weeks, but they will
die if they suck in too much.
"The public reefs on the east side of the Mississippi -
American Bay, Black bay, Breton Sound - that is where most of our
seed comes from, and they might be closed for a long time,"
Tesvich said.
Earl Melancon, an oyster expert at Nicholls State University in
Thibodaux, said he has already written off this year for oyster
production.
"If you lose an oyster reef, it takes three years minimum to
get it back into production," he said. "And it could take five
years."
Oyster reefs lie a few feet under the water and span the
Louisiana coast. Often, farmers help build oyster grounds by
dropping concrete and other hard surfaces into the water so oyster
larvae can attach to them.
Most likely, the oysters that will do the best will be those
close to the Gulf of Mexico, where there's more salt water.
But those shellfish could be vulnerable to the oil, which has
been washing into coastal waters since the end of April.
The Louisiana oyster spawns by releasing larvae that swim
through the water and find places to sit on and grow. The oyster
goes through various stages - from growing a leg to losing it,
changing sexes and growing a shell by extracting calcium carbonate
from the water - to the point where it is big enough to sell on the
market, between two and four years old.
From now until next spring, Melancon said the big question will
be whether there will be a new brood of oyster larvae planting
itself on Louisiana's reefs.
The industry already was reeling from several bad years marred
by hurricanes, heavy rains and over-harvesting - a situation made
worse by the oil spill and the freshwater diversions, Tesvich said.
Plus, a more limited supply could drive up oyster prices. But
Banks said the industry has rebounded before.
"The good news is that we have been this low before," Banks
said. "Mother nature is amazing and oysters can come back."

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