Responding to the oyster fishery collapse in Apalachicola Bay, experts with the University of Florida’s Institute of Food and Agricultural Sciences and Florida Sea Grant are joining forces with local seafood producers to find ways of restoring sustainable populations of the area’s world-famous oysters.
The Apalachicola River flows into the bay at the town of Apalachicola, creating a unique environment that is nearly perfect for oysters to grow. Persistent drought throughout the southeast U.S. has drastically reduced freshwater inflows into the bay, stressing oyster populations and other important fisheries. (Adapted from Google Earth)
Apalachicola, a heritage fishing community in the Big Bend region off the northwest coast of Florida, is Florida’s epicenter for production of oysters that are prized for their outstanding quality and taste. Oysters have been harvested and processed here for decades, with the skills of the trade passed down from generation to generation.
Today this unique oyster fishery is on the verge of collapsing for a variety of reasons, some due to nature and perhaps some man-made. Apalachicola Bay traditionally has been a perfect place for oysters to grow. It has natural geographic features on its bottom called ‘bars’ that support colonies of oysters, and it historically has received high inflows of nutrient-rich freshwater from the Apalachicola River.
This simple diagram shows how birds and fish are dependent on microscopic algae, which are fed by essential nutrients brought into the bay by the Apalachicola River. (Florida Sea Grant image)
The river’s freshwater flow does a number of things for the Bay. In the wet season, after heavy rainfall in the upstream basin, high river flows push predators that cannot tolerate freshwater out of the system, keeping their numbers in check so they do not overtake the oysters that they readily consume when they can get into the Bay. These predators include crabs, boring sponges and crowned conchs.
This simple diagram shows how birds and fish are dependent on microscopic algae, which are fed by essential nutrients brought into the bay by the Apalachicola River. (Florida Sea Grant image)
The freshwater flow also maintains a low enough salinity in the Bay that oysters do not develop high levels of a pathogen called Perkinsus, which can lead to disease in oysters if it becomes abundant (at higher salinity). Perkinsus is not harmful to humans, but can decimate an oyster population if it becomes abundant.
River inflows also bring essential nutrients, including phosphorus, nitrogen, and organic carbon. These nutrients fuel the growth of algae and bacteria, which make up the base of a food web that supports a diverse community of shrimp, oysters, fish, shore birds and other plants and animals.
During the last two years, a severe drought in Georgia, where much of the water in the Apalachicola River originates, has dramatically reduced freshwater inflows to Apalachicola Bay. Adding to this problem are large withdrawals of water from upstream reservoirs for use by residents of Atlanta, a nuclear power plant in Alabama, and Georgia and Alabama agriculture.
Oystermen have noted declines in abundance of a wide range of aquatic animals in the bay, and they say that their harvest has dramatically declined. This situation may reflect a variety of stressors, including increased predation as salinity in the bay has increased without the typical rate of freshwater inflow, perhaps nutrient limitation of the food web, and a high level of oyster harvesting.
Data from the Florida Department of Agriculture and Community Services also shows a strong and unprecedented decline in oyster landings in 2012 compared to earlier years.
Harvesting of oysters increased after the BP oil spill in 2010, when the state issued a large number of new oyster harvesting permits, and allowed higher rates of harvest than traditionally occurred – the idea being to get oysters before oil came to the bay (which never occurred). Despite a return to pre-spill regulations, harvesting rates remained high in 2011, and evidence shows that there is substantial harvesting of sub-legal (less than 3 inch) sized oysters.
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In essence, the period from 2010 to 2012 may have been a ‘perfect storm’ for the oyster fishery in Apalachicola Bay – and – the storm may not be over, as drought is predicted to extend into 2013 in the river basin.
University of Florida/IFAS is responding to this crisis with a research team led by Karl Havens, the director of the Florida Sea Grant program.This UF Oyster Recovery Team includes about a dozen UF researchers with a broad range of experience and knowledge about oysters and coastal ecosystems in Florida, as well as researchers from Florida State University, Florida Gulf Coast University, Florida A&M, the state regulatory agencies, the Northwest Florida Water Management District, and about a dozen representatives from the oyster industry and other fishing-related businesses in Apalachicola.
To date, the research team has assembled a massive array of data from the state agencies and has collected hundreds of samples of oysters, fish, water and sediments. Researchers are looking for signs of increased infection, signs of oil or dispersant from the BP oil spill, and evidence of over-harvesting. They also are looking at predation rates on oysters and how they relate to salinity of water at different locations in the Bay.
At the same time that the scientists are doing their work, a group of oystermen from Apalachicola have formed a group called SMARRT (Seafood Management Assistance Resource and Recovery Team) that aims to work with the state regulatory agencies to develop a process to ensure that the oyster industry has long-term sustainability.
The expected products from the UF Oyster Recovery Team include a white paper and public presentations providing information on:
- the current state of the bay;
- changes that can be documented from the data over the last five years; and
- suggestions for sustainable management of oysters in a wide range of environmental conditions.
These products are expected in the first quarter of 2013. In the meantime, in addition to analyzing data to develop the report, UF researcher are working with SMARRT to develop experiments that can be done in concert with oyster relaying and shelling (two restoration methods) so that they can be learning experiences to guide future restoration events.
One fundamental approach of the Team is helping the community members move away from a focus on factors they cannot control, such as drought and rainfall, toward factors they can control, such as how oysters are harvested in space and time, and how restoration programs are conducted.
