SCCF’s oyster reefs completed, now time for them to get cozy in new underwater homes
SCCF’s oyster reefs completed, now time for them to get cozy in new underwater homes
If you’ rea noyster,w el comeback. Southwest Florida environmentalists anticipate that an ambitious project to restore oyster beds will begin paying dividends this year. Acres of new oyster beds in Tarpon Bay and San Carlos Bay off Sanibel and the Matlacha Pass National Wildlife Refuge off Pine Island were completed in January. Stiff winds had slowed barge crews dumping reefing shells in the bays. An earlier oyster project in Clam Bayou on Sanibel has proven successful.
People and natural causes have staggered oysters in Southwest Florida, state wildlife authorities report. Experts plan to monitor new oyster communities for two years.
A small volunteer army and a marine contractor, tons of quarried and donated shells, and state funding in 2015 came together to restore oyster reefs in Gulf estuaries, says Eric Milbrandt, a marine biologist and director of the Sanibel-Captiva Conservation Foundation (SCCF) Marine Laboratory, the project’s architect and coordinator. Oysters had suffered a catastrophic depletion, he says. “We’re trying to make [oyster] habitat better around Sanibel to help them build more resilience.”
In a white paper Milbrandt co-authored in 2015, he and others asserted habitat loss is the greatest threat to ocean life. It’s the same story― development and coastal population growth driving the losses with activities such as channel dredging, sewerage and chemical discharges, and oyster overharvesting. Natural flooding, beach erosion and sand drift, storms, diseases and other natural causes have contributed to oyster, mangrove and seagrass devastation, among a chain of ecological calamities in coastal Florida. It’s estimated that oyster populations have suffered 85 to 90 percent losses over five decades.
Oysters, or saltwater clams, thrive on reefs―topping the menu for fish, whelks and crabs. Their true value is as ecosystem engineers, filtering food and oxygen by pumping water across their gills. In fact, one adult oyster can filter 50 gallons in 24 hours, according to the Florida Fish and Wildlife Conservation Commission. Feeding oysters take in viruses, bacteria, phytoplankton, algae, sediments and chemical contaminants in the water. Of course, they’re tasty on ice, which contributed, oddly, to the campaign in the Gulf― restaurants in and around Sanibel donated thousands of shucked oyster shells. A Charlotte County firm also provided truckloads of excavated fossil shells. Another contractor, SteMic Marine Construction, trucked fossilized shells from an Arcadia quarry to San Carlos Bay. The firm’s barges hauled the shells to selected sites, where two acres of individual reefs were placed in tidal water about waist deep. The oyster work was “very cool,” SteMic vice president Mike Jones says. “Certainly different.”
Serious oyster restoration started in 2006 with construction of a box culvert entering Clam Bayou on Sanibel. It had been a 400-acre warm-water vacationland for oysters and other sea creatures. Tidal-flow blockage of Clam Bayou from shifting sand, however, killed off virtually every living thing in the bayou, including seagrasses, mangroves, fish and oysters. Mangrove
replanting campaigns followed culvert construction. There were mixed results, Milbrandt says, largely because mangroves are sensitive to the balance of salt and tides. Oyster reefs introduced to Clam Bayou showed positive settlement rates.
The Florida Department of Environmental Protection (DEP) initially awarded a pair of $500,000 grants to reestablish oyster populations and seagrass beds in the Indian River Lagoon’s St. Lucie Estuary along the state’s east coast and the Caloosahatchee Estuary in Southwest Florida. The grants went to the Florida Oceanographic Society and to SCCF. Both agencies created restoration and monitoring programs. “The St. Lucie and Caloosahatchee estuaries are vital natural resources that must be maintained and supported,” DEP Deputy Secretary for Ecosystem Restoration Drew Bartlett said at the time. “These projects will help restore healthy oyster populations and seagrass beds, which are important to these ecosystems and our economy,” he said, adding that harmful freshwater discharges have resulted in losses of oysters and seagrasses in both estuaries.
The Florida Oceanographic Society has been restoring oyster reefs and seagrasses since 2005. Its shellfish hatchery has produced millions of oysters for restoration programs. Additionally, the society has grown five common native species of seagrasses for testing and success studies. SCCF will also grow and replant founder colonies of submerged aquatic vegetation to build resiliency by providing a source of healthy reefs and vegetation, a DEP report states.
Back on Sanibel, Milbrandt says nearly 80 volunteers were keys to the oyster project’s success, with a cross-section of ages and backgrounds pitching in to build reefs, bucket by bucket. “It was great,” he says.
The St. Lucie and Caloosahatchee estuaries are vital natural resources that must be maintained and supported.” —Drew Bartlett, Florida Department of Environmental Protection Deputy Secretary for Ecosystem Restoration