Are oysters the key to battling red tide in Florida?

A single oyster can filter as much as 50 gallons of water a day. Combine millions of them and they could be an affective tool in keeping red tide at bay in some areas of the county’s waterways.
A single oyster can filter as much as 50 gallons of water a day. Combine millions of them and they could be an affective tool in keeping red tide at bay in some areas of the county’s waterways. Raleigh News & Observer/MCT

As sea life continues to be devastated in the Gulf of Mexico off Anna Maria Island, an unlikely hero has emerged, or in this case submerged, to potentially battle red tide should it creep into other Manatee County waterways.

One oyster filters between nine and 50 gallons of water a day, according to Sandy Gilbert, CEO of START, which launched the Gulf Coast Oyster Recycling & Renewal program a little more than a year ago. The organization was started in 1995 during another massive red tide bloom in Manatee County and has been working to restore the county’s shellfish population.

“Clams and oysters are an important part of our ecosystem,” Charlie Hunsicker, director of the Manatee County Parks and Natural Resources Department, told the county commission Tuesday. “They are little creatures that are part of a bigger plan, and we believe, part of the solution to help with red tide.”

About 280 volunteers have been working this past year bagging oysters and placing them along the Manatee River and in strategic locations in Sarasota Bay and Robinson Preserve. Before being named the Manatee River, the waterway was known as Oyster River. The over-harvesting of shellfish over the years decimated the population and START is looking to give oysters another chance to thrive.

That work has been ongoing and combined with county sewer and water infrastructure improvements, the result has been consistently higher water quality in Sarasota Bay since the 1950s.

“Oysters are incredible filters and represent a natural and cost-efficient way to keep the bay and your rivers clean,” Gilbert said. “And it can keep red tide at bay.”

The organization has seeded more than two million oysters and clams with another 250,000 expected by next month. Gilbert said they are a local species and can live up to 30 years.

“That’s a long time to be working in the bay and they do eat red tide,” he said.

Another aspect to the project is the partnership between START and the Ed Chiles Restaurant Group on Anna Maria Island and Longboat Key. The restaurants keep the shells after customer use and after storage, deliver them to the Perico Preserve to cure. The shells are then placed at what is being called “oyster reef” at Robinson Preserve where the shells are occupied to make new oysters.

“In a year, we’ve dropped 57,000 pounds of oysters,” Gilbert said. “That’s 26 tons not in your landfills and serve as the base of this oyster program. The shells are producing 23 percent more oysters.”

Gilbert has other restaurants interested in participating but had no way to deliver them to Perico Island for the curing process. Waste Pro has stepped in, donating bins to the restaurants for storage until Waste Pro drivers can pick them up to make the delivery. The tonnage of empty shells that can be put to better use is expected to rise from 26 tons to 85 tons over the next several months.

The city of Bradenton also is getting involved and has agreed to build a living shoreline of oysters instead of a seawall for the eventual eastward expansion of Riverwalk. Realize Bradenton is involved, as well, and will be hosting the Shoreline Shinding, a free community festival to raise funding for the program.

The festival will take place Oct. 13 on the existing Riverwalk.

The red tide debate

Red tide blooms when a higher-than-normal concentration of a microscopic algae, most often associated with Karenia brevis, is adequately fed with pollutants. Karenia brevis is a naturally occurring algae, but needs to be fed in order to bloom into red tide, which attacks the central nervous system of sea life.

Gilbert said scientists may have varying opinions but the one thing that riles his organizations is when red tide itself is referred to as a naturally occurring event.

“Let’s be frank,” he said. “We live between the two biggest nutrient dumps in the country. Red tide tends to come from the south, but the current lines from the Mississippi River and the Caloosahatchee River shows you the proof. The deal is, we need more help from the state and federal governments.”

Following the massive loss of life of an unnamed hurricane in 1928, Florida rushed to build the canal systems that exist today in order to quickly remove water. Gilbert said the system works to get water moving, but the water drains so quickly, that it brings with it the kind of agricultural byproducts that help to create red tides miles away.

“Yes, the organism is a natural phenomenon, but the magic is the food that becomes a big bloom,” Gilbert said. “Take a look at your current flow. Where does it go? It goes out into the Gulf, feeds red tide and the red tide comes back here. Certainly, Lake O needs to be dealt with and the water needs to flow south over land so the Everglades gets more water, which cleans the water before it gets to our waters. It’s pretty basic.”

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