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Oysters to cut pollution to shell of its former self

By RACHEL SIMMONSEN
rachel_simmonsen@pbpost.com
Staff photos by VADA MOSSAVAT
September 16, 2006

Staff Photos by VADA MOSSAVAT Research assistant Heather Holberger adds oysters to a reef created in May from 400 tons of oyster shells.

Heather Holberger eased over the side of the boat, grabbed a bucketful of oysters and set to work on the task at hand: cleaning up the St. Lucie Estuary.

On Friday, the research assistant with the Florida Oceanographic Society led a team of volunteers in adding about 8,000 oysters to a newly formed reef in the St. Lucie River near Martin Memorial Medical Center. Oysters improve water quality by filtering out pollutants as they eat, so scientists hope to restore the 470 acres of oyster beds that thrived here decades ago, before the brackish estuary was flooded with freshwater runoff because of development and massive discharges from Lake Okeechobee.

Now only about 100 acres of oyster beds remain, but "if we get the population back up to what it used to be, the St. Lucie will become a lot healthier," Holberger said.

In May, the oceanographic society used money from Martin County and the South Florida Water Management District to dump about 400 tons of oyster shells into shallow waters east of the Roosevelt Bridge. The shells formed the foundations of reefs that will become habitat for oysters found naturally in the estuary, as well as those scientists add.

"We're already starting to see a comeback" among the oysters, said Mark Perry, executive director of the oceanographic society.

Two to 3-month-old ousters (center) are raised in mesh bags until 5 to 6 months old, when they are placed on reefs to filter water.

Friday was the first time staff added oysters that volunteers raised. As part of the restoration effort, Research Aquaculture Inc. is spawning oysters at its facility on the campus of the oceanographic society on South Hutchinson Island. When the oysters are about a month or two old, they're placed into mesh bags and tied to the docks of homeowners along the St. Lucie River.

On Friday, Holberger and volunteers stopped by three of the homes, retrieving oysters that had grown in the past three months from the size of peas to the size of silver dollars. The oysters - now about 5 or 6 months old - were dumped into buckets, then plopped by hand atop the shell reef near the hospital.

Friday's work was just the beginning, Holberger said. Each adult oyster can filter about 50 gallons of water a day, and scientists hope to bring the estuary's population to 10 million.

And so the cycle started anew Friday. After taking the silver-dollar-sized oysters from the docks to the reef, volunteers tied new mesh bags to the docks, dangling them into the water. Inside: a new batch of pea-sized oysters that, come another 3 months, will become another layer on the oyster reefs.

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