By Michelle J. Lee, Providence Journal Environment Writer
December 4, 2006
BRISTOL — From a distance, the floating cages look like misshapen buoys or lobster pots. Each cage contains six wire bags with 5,000 tiny juvenile oysters, the seeds that could clean up the waters of Bristol Harbor and Narragansett Bay.
In an attempt to turn the tide against the dwindling oyster population, 18 volunteers throughout the state grew oysters off their boats and moorings this summer and fall for the Rhode Island Oyster Gardening for Restoration and Enhancement program.
Steve Patterson, the program coordinator, helped build the cages and monitored the oyster growth. For the past two weeks, Patterson collected 13 of these “floating gardens” and brought them back for sorting at Roger Williams University.
RI-OGRE started in June to revitalize the native Eastern or Atlantic oyster. During the summer, oyster seed was cultivated at the university’s shellfish hatchery. The juvenile oysters, or spat, were attached to shells in wire bags, and distributed to 18 volunteers throughout the state in August to grow in Bristol Harbor, the Sakonnet and Potowomut rivers and Point Judith and Quonochontaug ponds.
On Saturday, about 100,000 juvenile oysters will be released in Bristol Harbor onto a large “culch”— a bed made of 2½ tons of clam shells. Ideally, these thumb-size oysters will attach there, grow to adulthood and remain there to improve the water quality.
A single adult oyster can filter 50 gallons of water a day and live up to 25 to 35 years if undisturbed, said Dale Leavitt, an assistant biology professor at Roger Williams University and the RI-ORGE founder and technical assistant.
“Fifty gallons of water a day, 365 days a year, thousands of oysters, they’re moving a lot of water,” Leavitt said.
The program is funded with $35,000 from the Rhode Island Aquaculture Initiative.
Historically, oysters thrived in Narragansett Bay and supported a significant amount of the Rhode Island shellfish industry.
In 1864, the state adopted laws that opened up sections of Narragansett Bay to oyster cultivation. After the Civil War, production grew and eventually produced 8.7 million pounds during its peak, in 1908, according to RI-OGRE data. Oyster cultivation in the early 1900s generated what would be the equivalent today of $50 million to $90 million in revenue.
The crash came in the wake of the Great Hurricane of 1938. “That was the coup de grâce,” Leavitt said. “Oysters at that time were stressed in the Bay. There were contamination problems and fair amount of fisheries. Between overharvesting [and] contamination, the hurricane pushed them over the edge.”
There were a few isolated pockets of oyster beds afterward but the population never recovered, Leavitt said. Further complicating matters, the infectious parasitic diseases Dermo and MSX— harmless to humans but lethal to oysters— damaged many of the remaining oysters. The diseases also devastated oysters in the Long Island Sound and in Chesapeake and Delaware bays.
To prevent problems, the spat for the program came from mature oysters grown in local waters. The floating cages were also placed in waters that were safe for shell fishing. Patterson boated daily to check on their progress, cleaning the oyster bags for better growth and removing seaweed, sea squirts and other debris.
Only one floating cage from Portsmouth escaped during a huge rainstorm in October. Patterson said he found the cage at McCorrie Point, suspiciously missing six bags of oyster spat.
For the volunteers, the program has been a great educational moment.
Lisa McGreavy, a Tiverton resident, said her family learned a lot about oysters and they were glad to help in their small way by keeping the floating cage connected to their boat, Another Girl. Her daughter, Elizabeth, 15, even wrote a science report on oyster gardens.
In the future, McGreavy, a senior environmental planner for the Department of Environmental Management’s Office of Water Resources, said she hoped the filtration could improve the water enough to stir the wild population to return. “Hopefully someday we’re going to see lots of oysters in Nanaquacket Pond again and the population will be able to sustain itself,” she said.
Tom Clegg, another Tiverton resident and program volunteer, said he loved watching the oysters grow from his mooring.
Clegg, 43, a retired shell fisherman, said he remembered a time when the oysters in the Sakonnet River were so plentiful people could rake them up on the beaches.
From the mid-1980s to the mid-1990s, the oyster population in the river briefly bounced back before the diseases devastated them again. “There were so many oysters it was unbelievable,” he said. “Tiverton went from super to nothing as soon as that hit.”
legg said he hoped the program could expand to include quahogs and scallops. “It’s a win-win situation for everyone, for the whole State of Rhode Island [and] the shell fishermen, keeping the water nice and clean,” he said.
Once the oysters are planted in Bristol Harbor, Leavitt plans to monitor their growth using an underwater camera. The floating cages in Point Judith and Charlestown will be left to grow over the winter as a research project and will be added to other restoration projects.
Leavitt and Patterson hope to obtain more money to continue the program and double the number of oysters grown. Leavitt said they would love to see the oysters rebound in Narragansett Bay and return to large, harvestable quantities.
They would also love to see oysters return to areas that are off-limits to harvesting, to purify the water and improve bay habitats.
“If we can do this on a yearly basis, the ecosystem will take hold,” Patterson said. “There will be shellfish. There will be sea squirts, crabs. It will be an underwater sanctuary.”
For information about RI-ORGE, call (401) 254-3707 or e-mail oysters@rwu.edu.
Michelle J. Lee is a fellow with the Metcalf Institute for Marine and Environmental Reporting.