November 5, 2007   

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Man-made oyster reefs in Va. seem to be thriving
Experts examine module lifted from bottom of Rappahannock River
Monday, Nov 05, 2007 - 12:08 AM Updated: 08:36 AM
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MOSQUITO POINT Scientists got a rare look at sunken treasure yesterday as they eagerly watched a man-made oyster reef emerge from the bottom of the Rappahannock River.

Pulled out by a crane mounted on a barge and hovering over the river, the 6-ton concrete rectangle came up dripping salt water and mud crabs and bristling with clues that Virginia's native oyster might yet find a future in the Chesapeake Bay.

"This is what we were waiting to see," said Virginia Institute of Marine Science professor Rom Lipcius as he reached out to touch a hand-sized oyster growing from the module that had been sunk nearly seven years ago.

The size of the oyster suggests it is 5 or 6 years old. That means it managed to survive and propagate despite disease onslaughts that have all but destroyed the bay's once-mighty oyster population.

Hundreds more of its kind in all sizes wrapped the module like a rough wool sweater.

Best described as a concrete layer cake made of 7-foot wide by 7-foot long layers of honey-combed precast concrete, the module had been sitting on the bottom in 28 feet of water since 2000. It marked the center of a broad field of concrete rubble placed in the river beginning in 1999 as a test of its appeal to oysters.

Having studied a portion of the reef two years ago, Lipcius suspects the module and surrounding rubble have the densest oyster population in the bay.

"What you don't see are the 170 reefs out here. Each is seven layers of 12-foot by 12-foot sections of concrete pavement," Lipcius said.

He estimated that there are no less than 2 million and possibly more than 5 million oysters amid the reefs.

An iconoclast named Robert W. Jensen conceived the idea of using scrap concrete as oyster reef several years ago when the nearby Norris Bridge was undergoing major renovations.

Jensen got state approval to create two reef sites in the lower Rappahannock. He says the idea ought to be expanded throughout the bay's oyster-growing regions to revive the species.

Jensen dismisses skeptics who long ago concluded that what he was really promoting was a cheap place for contractors to dump used concrete.

"I'm doing this because it's something that needs to be done," he said "If I needed money, I'd be hustling used cars."

Jensen deployed the reefs and checks on them periodically with the help of McLean, a Maryland-based marine-contracting firm that did the Norris Bridge repair work.

One of the company's floating cranes was on the river last week to replace a worn fastener in a bridge-support beam. That gave Jensen and Lipcius a chance to use the crane to lift the concrete module for the first time since it had been dropped overboard.

VIMS graduate student Russell Burke is writing his dissertation on Jensen's effort. It is titled "The Use of Alternative Substrate for Native Oyster Restoration." Burke said has he scraped mud, mussels and oysters off a section of the module.

Lipcius said the layers of concrete comprising the module can quickly increase oyster populations. Oysters need a clean hard surface for attachment after an initial start in life as free-floating larvae. All manner of aquatic life colonizes the modules. Artificial reefs, Lipcius said, attract fish, support oysters and other bivalves that filter and clean water.

Research continues on the structures. VIMS has deployed some of its own 4-foot by 4-foot modules in the bay near Poquoson for study purposes and is planning to place addition modules in the Lynnhaven River and Broad Bay near Virginia Beach.

The more Lipcius learns about the Rappahannock reefs, the more he likes them.

Yesterday, the concrete module pulled from the bottom sat on the barge deck like a profuse patio garden, in places fuzzy with red beard sponge, gnarly with sharp clusters of hooked mussels and literally wiggling with tiny fish called sculpins.

"All you have to do is look at it," Lipcius said, "and you know its productive."
Contact Lawrence Latané III at (804) 333-3461 or


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