http://www.nytimes.com/2009/08/04/sc...=1&ref=science

August 4, 2009

Oysters Are on the Rebound in the Chesapeake Bay

By HENRY FOUNTAIN

"After decades of overharvesting of oysters in the Chesapeake Bay and many
fruitless efforts to replenish them, scientists have re-established a
significant population of the shellfish along the Virginia shore.

Researchers from the Virginia Institute of Marine Science at the College of
William & Mary say that large experimental reefs created five years ago are
now home to more than 180 million native oysters. That is still a far cry
from the late 1880s, when the bay held billions of the oysters, Crassostrea
virginica, and watermen harvested about 25 million bushels annually. But
more larvae have been settling on the new reefs every year, the researchers
said.

The results, they added, suggest there is a potential for further
restoration in the bay by creating additional reefs where harvesting is
prohibited.

"What we need are thousands of acres of permanently restored sanctuary reefs
to turn this situation we have with the oyster around," said David M.
Schulte, a doctoral student at the institute and an author of a paper
published in Science last week that describes the work. The sanctuaries
would aid the oyster harvest by helping to seed nearby areas, but the
overall effort would benefit the bay in other ways, by helping to clean the
water and providing more habitat for fish, crabs and other marine life.

Mr. Schulte said that when he began the experiment, he assumed there would
be only a 10 percent survival rate among juvenile oysters on the reefs,
which are near the mouth of the Great Wicomico River, just south of the
Potomac. Throughout the bay, high mortality due to disease, as well as
overfishing, had reduced the population to about 1 percent of 19th-century
levels.

The current harvest is less than 200,000 bushels a year, and the situation
has become so dire that there is an elaborate proposal to introduce the
Asian oyster, C. ariakensis, as an alternative.

But Mr. Schulte said that in the first year of the study there was about a
30 percent survival rate on the reefs. "I was really surprised," he said.
"That's really what helped this project become what it has."

"We're hoping that the population in the Great Wicomico is stable," he
added.

A Virginia fisheries official said he was optimistic that the restoration
technique was working, but that the next several years would be critical.

"The looming question is whether what we're seeing is just a short-term
effect or long-term restoration," said Jack Travelstead, chief of the
fisheries management division of the Virginia Marine Resources Commission.
"Enormous numbers of oysters are thriving in that area, but oyster diseases
are still present."

He noted that in 1996 there was a very good spawn of oysters in the same
river, but that as they grew most eventually died from disease. "We're a
little bit concerned that we might experience that here," he said.

A key to the success of the new reefs, Mr. Schulte said, is their height and
extent. The reefs, which were created by the United States Army Corps of
Engineers by dumping oyster shells, are 10 to 18 inches high and cover more
than 80 acres, with the largest about 20 acres.

In earlier restoration efforts, most of the reefs were lower, so the oysters
had to cope with stirred-up sediment. Oysters are filter feeders, and
filtering out sediment expends energy they could use for growth and makes
them more susceptible to disease. Having the shellfish higher in the water
column - they tend to grow on top of the reef, in thick layers - appears to
keep them healthier.

Most of the earlier reefs were also smaller, usually about an acre in size.
Mr. Travelstead said the new effort had shown that "it's not just build it
higher, but build it larger and inundate it with healthy broodstock that is
showing some signs of disease resistance."

"This is a first attempt at altering the scale," he added. "But scale means
money, and that's pretty hard to find these days."

Scott McGuire, a volunteer with the Coastal Conservation Association of
Maryland, a sport fishing group, said that his organization supported the
creation of more sanctuaries like the ones in the study. "This type of
research is what we've been asking for a long time," he said. Oysters, he
said, are a keystone species in the bay. "They filter the water and provide
all kinds of ecological niches for other organisms. And they create lots of
good fish habitat."

Ken Smith, president of the Virginia Watermen's Association, said he was not
surprised by the results of the study. He said watermen had been putting
oysters in cages and raising them off the bottom, "and we have gotten the
same results that the scientists have gotten."

Mr. Smith said his group, too, would support more sanctuaries if they would
contribute to the health of the bay and indirectly to the watermen's
livelihood. Harvesting oysters used to be his primary source of income, he
said, "but for 20 years, it's been dead."

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Gregory Morrow wrote:
> http://www.nytimes.com/2009/08/04/sc...=1&ref=science
>
Interesting article, Greg - thanks for posting. Incidentally, it was
mentioned in there that the introduction of Asian oysters was being
considered. Thankfully, that idea has been abandoned because of fears
that the foreign oysters would have a harmful effect on our native
crop.

"Dora" > wrote:

>Gregory Morrow wrote:
>> http://www.nytimes.com/2009/08/04/sc...=1&ref=science
>Interesting article, Greg - thanks for posting. Incidentally, it was
>mentioned in there that the introduction of Asian oysters was being
>considered. Thankfully, that idea has been abandoned because of fears
>that the foreign oysters would have a harmful effect on our native
>crop.

I also enjoyed reading about the bay. I wonder how the blue crabs are
doing? I read a great book about 25 years ago on the blue crab
fishery "Beautiful Swimmers" if memory serves.

And while we probably do understand nature a little bit more than 30
years ago, I'd bet there are still large holes in this understanding
and intentionally introducing species is very risky. About 30-40
years ago a non-native fish was intentionally introduced by a
government agency and that turned out to be a total disaster with this
new fish eating the larval/juvenile stages of highly desirable game
fish. http://en.wikipedia.org/wiki/Bluestripe_snapper DOH!

On a more positive note, I usually wonder every late Nov. who the
ancient genius was that decided to use oysters as part of the
stuffing/dressing for turkeys and other poultry? Was alcohol
involved? Probably was for the Tur-duc-ken! :-)

jj wrote:
>
> I also enjoyed reading about the bay. I wonder how the blue crabs
> are
> doing? I read a great book about 25 years ago on the blue crab
> fishery "Beautiful Swimmers" if memory serves.
>
The blue crab situation is still poor but slightly improved because of
more diligent control efforts. Restrictions on the taking of female
crabs are certainly having their effect. Common sense indicates that
if female crabs are taken, both by harvesting in the season and
dredging in the winter, future catches will be impacted. Government
officials are finally waking up to that.

Yes, "Beautiful Swimmers" was a great book. for which William Warner
won the Pulitzer prize. We boated on the Bay for over 30 years and it
never ceased, or ceases, to amaze me. What a learning experience.