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Luring oysters to lie down

The waters of Tampa Bay once supported a thriving commercial oyster industry. But with development came pollution and large-scale habitat destruction around the 1950s and '60s. ¶ The oyster beds began to disappear and poor water quality made the remaining mollusks unsafe to eat. As the oysters declined, so did other species, such as red drum, which count on oyster beds for survival. ¶ But what humans destroyed will soon be rebuilt.

Nature's sea walls

Two years ago, Pinellas County officials approached Tampa Bay Watch, a leader in bay restoration, with a problem: the wakes from boats zooming by Weedon Island were causing the shoreline to erode.

"Oysters do many positive things in the environment," said Peter Clark, the environmental group's executive director. "But one of the most important is they help reduce wave energy."

Oysters live in colonies. With each generation, an oyster bar gets larger and larger. In the 1800s, Tampa Bay had oyster bars that would stretch for hundreds of feet.

These massive oyster bars would absorb the wave action during high tides and storms, allowing more delicate habitat, such as sea grass beds, to thrive inside protected waters.

"Weedon Island was losing mangroves and large, mature pine trees," Clark said. "Without the oyster bars, there was nothing to protect the shoreline."

Filter feeders

Oysters can be found from Canada's Gulf of St. Lawrence, throughout the Gulf of Mexico and into the West Indies. These mollusks feed on plankton and are prey for everything from sea anemones to red drum.

Here in the gulf, oysters can grow to 3 inches long in 18 to 24 months and 6 inches long in five or six years. Biologists believe gulf oysters can live for 25 to 30 years and reach a maximum size of nearly 12 inches.

Sexually maturing at around four months, Crassostrea virginica takes about 20 days to settle to a hard surface on the bay bottom and cement itself in place. Once one oyster finds a home, others soon follow. Before you know it, you have a colony of thousands.

As they feed, each mollusk can filter about 10 gallons of bay water each hour.

"It is pretty simple," Clark explained. "The more oysters you have the cleaner the water."

Food for fish

Bill Arnold, the state of Florida's "Mollusk Man," has been studying oysters, scallops and clams for more than 25 years.

"They are like the cows of the sea," he said. "They graze and turn what they eat into meat."

Every angler knows that the best place to look for fish, including reds and cobia, is around oyster bars. These predators come for the oysters themselves, but also a myriad of other organisms that live in and around the reef.

"It is essential fisheries habitat," Arnold said. "They are extremely important to a variety of species and one point or another during the life cycle."

Because oyster bars provide a protective barrier for the sea grass meadows, they also indirectly support the snook and spotted seatrout populations.

"You need the oyster reefs and the grass beds for the whole system to work," Arnold said.

Muscle, sweat
and oyster shells

Tampa Bay Watch has had great success in recent years with its oyster dome program. Concrete "reef balls" placed along shorelines and seawalls give oysters a solid place to secure themselves and grow.

These oyster domes, which are hollow, absorb breaking waves. They also provide a place for tiny fish and crabs to hide from predators. After a dome is in the water a few months, the concrete becomes covered with living oysters, which in turn attract other marine life.

Tampa Bay Watch has taken its habitat restoration one step further. The organization's Community Oyster Reef Enhancement program is now building actual oyster reefs out of discarded oyster shells throughout the bay area.

Old oyster shells are purchased by the ton and delivered to local boat ramps, where they are then shoveled into 5-gallon buckets or packed into 20-inch shell bags by community volunteers.

The oysters are then transported by boaters out to reconstruction areas, where they are lined up to mimic an actual oyster reef, which will attract any free-floating oyster spat.

The Weedon Island
success story

In October, Tampa Bay Watch volunteers spent two days building oyster bars at Weedon Island. Last week, they returned to finish the job.

"We had a total of 205 people show up to help," Clark said. "They deposited 69 tons of clean oyster shells along 630 feet of shoreline. That was enough to build six different sets of oyster reefs."

In past years, Tampa Bay Watch spent about $5,000 to $6,000 a year to purchase its oysters shells. But last week, the environmental group announced a partnership with a major bay-area restaurant, Crabby Bill's of Indian Rocks Beach. Clark estimates this will save the group between $3,000 and $4,000 a year.

"We produce a ton of oyster shells a week," said Matt Loder, son of the restaurant's founder, "Crabby" Bill Loder. "Instead of going into a landfill, we can put the shells back in the bay."

Clark said he has great hopes for the partnership.

"It makes sense to recycle oyster shells," he said. "I think this is a win, win situation for everybody."

Luring oysters to lie down 03/20/08 [Last modified: Friday, March 21, 2008 8:21pm]

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