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The Oysters of Apalachicola Bay
Franklin County’s oyster industry is based on the highly preferred “Eastern” oyster, also known by its scientific name Crassostrea virginica. Oysters here grow rapidly (the fastest in the country) in these waters reaching marketable size in less than two years. Apalachicola Bay’s wild oysters are diploids which means that they spawn during the summer to release eggs and sperm into the warm salty water. A single female oyster can discharge 10-20 million eggs per spawn and as many as 100 million per season. Upon fertilization, the free-floating larvae develop quickly, attach to a hard substrate and become a tiny oyster called “spat.” Once attached to substrate, these bivalve mollusks form large colonies called reefs, bars or beds. Oysters feed by drawing in water with their gills to extract nutrients.
Apalachicola Bay, including the waters of St. George Sound and St Vincent Sound, provides an ideal environment for oysters. The 210 square mile estuary is wide and shallow; depths in Apalachicola Bay average only six to nine feet at low tide. The estuary is dominated by the Apalachicola River which provides nutrient-rich fresh waters vital to the Bay’s natural productivity. There are more than 7,000 acres of public oyster “bars” in the Apalachicola Bay area.
Apalachicola Bay is historically the premier wild oyster harvesting area in the state. At one time, the Bay supported an expansive oyster reef ecosystem that was considered the healthiest in the nation. Franklin County waters once produced 90% percent of Florida’s oysters and 10% of the nations’ supply.
Oysters were sold locally as early as 1836, harvested much the same as they are today with scissor-shaped tongs hoisted aboard shallow-draft skiffs. By 1850, oysters had begun to be packed in barrels and shipped aboard steamers headed north or to other neighboring states. During the Civil War (1861-1865) no oyster business was done but at its close, shipments resumed and increased.
Historically, the commercial oyster industry has been affected by weather and man-made influences. Freshets (influx of fresh water into the Bay), hurricanes and even documented severe freezes dating back to the 1890s have impacted oyster production in and around Apalachicola Bay.
More recently, the harvest of “wild” oysters dropped dramatically in 2013 following years of decreased freshwater flow conditions throughout the Apalachicola-Chattahoochee-Flint River basin. The collapse of this fishery had devastating impacts to Apalachicola Bay oyster harvesters, seafood processers, and the community. In 2013, the U.S. Secretary of Commerce declared a federal fisheries disaster for Florida’s oyster industry and FWC began working with industry and the community to address concerns for this fishery. Despite taking a number of significant management actions since 2013, adult oyster abundance and juvenile recruitment continued to remain at historic lows, threatening long-term sustainability of the Bay’s oyster population. In 2020, Apalachicola Bay’s natural oyster population dwindled so precipitously that the Florida Fish and Wildlife Commission suspended the harvest of wild-caught oysters from public harvesting areas until 2025. Since then, scientists who are studying the problem say conditions are improving and the oyster populations are slowly rebounding for the public oyster bars.
About Apalachicola Bay Oysters
Eastern oysters are distributed along the east coast of North and South America, the Caribbean, and the Gulf of Mexico. They prefer shallow estuaries with moderate salinities (15-25 ppt). Oysters spawn by releasing eggs and sperm into the water column. Some spawning occurs throughout the spring and summer, with peak spawning occurring in the fall. Once fertilized, larvae spend about two weeks in the water column before settling on hard surfaces as small oysters, or “spat.” Although spat will settle on almost any hard surface, they have a higher tendency to settle on existing oyster shell/reefs. Once settled, the oyster will spend the remainder of its life attached. It takes about 12-16 months for an oyster to grow to a legally-harvestable oyster (three inches).
Oysters are ecologically important and provide a wide variety of ecosystem services (i.e.,functions that promote healthy ecosystems). They are somewhat unique in that they create their own habitat. New generations of oyster settle on existing shell material, which results in a complex, three-dimensional natural structure that continues to expand as oysters grow or new generations recruit to the oyster reef. In doing so, they provide habitat for thousands of species and other organisms, such as mussels and barnacles, as well as nursery and foraging habitat for a number of important species, such as shrimp, flounder, red drum, spotted seatrout, crabs, groupers, and other small prey.
Oysters are filter feeders and it’s estimated that an individual oyster can filter nearly two gallons of water per hour or 50 gallons of water per day. Oysters have the ability to directly improve water quality by filtering algae and other suspended particles from the water. Indirectly, oysters can improve water quality by reducing wave energy and stabilizing soft sediments. This promotes the growth of other ecosystems such as seagrass. Wave reduction also reduces shoreline erosion.
Appearance
- Reaches 8 inches at maturity.
- The shell has smooth edges and is oval in shape. The inside of the shell is white to off-white to brownish in color.
- The shell has a “cupped” shape to it, giving rise to its alternate name “American cupped oyster.
Biology
- Are of the shellfish family. Like mussels, clams and scallops they are bivalve mollusks, and have a hinged shell.
- Adults are sessile—they stay in one place—and inhabit both intertidal and subtidal areas.
- Have fast growth rates and high reproduction rates.
- First mature as males, then later develop female reproductive capabilities.
- Each female can produce over 100 million eggs during a spawning event.
Where They Live
Eastern oysters are found along eastern North America from the Gulf of St. Lawrence to the Gulf of Mexico. They are also found in the middle and lower Chesapeake Bay and its rivers.
Habitat
Eastern oysters live in brackish and salty waters from 8 to 35 feet deep. In some warmer areas, they are able to live in the intertidal zone. They attach to firm bottom areas, and to each other, to grow into reefs. These reefs provide habitat for fish, crabs, invertebrates, macrofauna, and birds.
Fun Fact
Middens—historic piles of oyster shells discarded after humans ate the meat—show that people have eaten Eastern oysters along the East Coast of North America for perhaps 2,000 years or more. For people who enjoy eating them, they are a treasured culinary delicacy. A single oyster filters over 15 gallons of water per day Bivalves feed on particles (phytoplankton and microorganisms) and filter nutrients in the water by pumping water over their gills, or “filter feeding.” Filter feeding improves water quality and transfers nutrients to bottom dwelling organisms. Bivalves are an essential link in the food chain for coastal tidal ecosystems. Researchers say a single 2.5-acre oyster farm can cycle the nitrogen from 40-50 people.