INDIAN RIVER COUNTY — Approximately 2,400 oyster seeds have been anchored in the Spoonbill Marsh with the hope that they will grow and filter about 60,000 gallons of mineral-laden water before the water goes out into the Indian River Lagoon.
“It’s just prime habitat,” said project manager Art Pfeffer.
Pfeffer had noticed that oysters were naturally clustering in the Spoonbill Marsh, which led to the idea that maybe more oysters planted there would solve the county’s problem of discharging wastewater from its Hobart Water Plant.
Working with Charlie Sembler, of Sembler and Sembler, a member of a longtime oyster farming family, the county has launched its $15,000 pilot project to determine whether the oysters will in fact scrub the discharge water clean.
“The outcome’s a little bit different,” Sembler said of oyster farming versus oyster planting for water filtration, but the principles are about the same.
“The dirtier the water, the better the oysters like it,” Pfeffer said, adding that the oysters will not be harvested for commercial use. “It’s not safe for consumption.”
In 90 days, they hope to be able to tell if the project is working. Mature oysters can process between 25 and 28 gallons of water daily. However, oysters take seven months to mature.
“That’s a lot of water,” Pfeffer said of the potential 60,000 to 67,000 gallons the oysters could filter.
Pfeffer explained that the county needed to find a new, more environmentally sensitive way to handle its castoff water from purging the filter membranes at the water treatment plant. Before, the county would discharge the water directly into the lagoon.
Faced with more stringent environmental standards from the state, the county was told it could no longer continue that practice.
Other governments, including the City of Vero Beach, invested in deep injection wells to dump the discharged water, Pfeffer said.
The county opted to try this “more innovative” route first, he said. A dozen 5-by-5 “beds” made of metal construction stud frames supported with chicken wire now house 200 oyster seeds in mesh bags, providing security for the oysters until they form their protective shells.
Sembler said he would be checking the 12 new oyster beds once or twice a day over the next 90 days and take sample oysters every 15 days to measuring the oysters’ growth and mortality rates.
The biggest concern Sembler has for the oysters’ success is the threat of predation. The Spoonbill Marsh has a large population of juvenile blue crabs, which prey on oysters.
“That’s something we’ll have to keep an eye on,” Sembler said.
Other threats to the baby oysters include algae, potential influxes of fresh water, and storms.
Crews will be taking water samples from around the site on a regular basis to measure the water quality.
Once the 90-day test project wraps, they are expected to report back to the Board of County Commissioners.
If, after 90 days, the oysters look to be growing and maturing, the county could ramp up the project by adding more oyster beds to the area to achieve the water filtration rate staff is shooting for.
Sembler said that if the project is a success, it could be replicated in other areas around the state for similar water quality projects.
“We’re all going to learn,” Sembler said.
Reporter Lisa Zahner contributed to this article.