Researchers investigating water flows on oyster reef restoration
Recently, Florida Gulf Coast University and Sanibel-Captiva Conservation Foundation researchers took their first cruise for a new collaborative project that is investigating how high flows from the Caloosahatchee may have an adverse impact on oyster reef restoration.
Planning for this summer’s research collaboration on bivalve larval transport began in February. The project extends previous work from a Master of Science thesis project by Bass Dye and advised by Dr. Felix Jose, with FGCU. The thesis focused on the complex currents in San Carlos Bay and the pathways developed a predictive model for the transport of free-swimming larvae. SCCF Marine Lab Director Dr. Eric Milbrandt served on the committee for the thesis, which was completed in 2018.
It is important to understand the transport of larvae to improve restoration and recovery of oysters in the estuary. It is estimated that oyster reefs are among the most imperiled marine habitats on earth, with losses of between 80 percent and 90 percent. Locally, reefs were destroyed during the construction of McGregor Boulevard and the remaining reefs have been highly degraded by the extreme high flows and drought conditions that exacerbate imbalances in river flows to the Caloosahatchee estuary.
On June 19, the first of 10 cruises focused on collecting larvae from sites in the bay, Matlacha Pass and Pine Island Sound. The goal is to validate predictions from a 3-D hydrodynamic model coupled to a larval transport model. Researchers will collect samples to enumerate bivalve larvae and quantify the number of oyster spat settling on shell strings. The research will provide new information to guide future restoration and help with understanding the impacts of high flow events. Initial findings suggest that larvae are transported out into the Gulf of Mexico during high flows and are never allowed the opportunity to settle on existing reefs.