Developing Sustainable Eastern Oyster (Crassostrea virginica) Farming in Georgia Through Evaluation of Grow-out Methodology, Distribution, and Marketing

View the project final report

Commodities

• Animals: shellfish

Practices

• Animal Production: aquaculture
• Education and Training: extension, participatory research, technical assistance
• Farm Business Management: budgets/cost and returns, farm-to-restaurant

Interest in eastern oyster aquaculture in Georgia continues to increase, but gear performance is limited. Growers have been interested in expanding into oyster aquaculture to diversify wild oyster harvest for more than a decade.  In 2014 the University of Georgia Shellfish Research Laboratory (SRL) established an oyster hatchery to provide oyster seed for research and for commercial use. To evaluated oyster aquaculture a multi-disciplinary approach was taken to evaluate oyster growth on intertidal leases, develop an oyster enterprise budget, evaluate the demand for oyster by restaurants, and work with growers on direct shipment. Covid-19 impacted restaurant and grower surveys. Since intertidal leases vary in size and conditions we examined oyster growth in tubes and found that oysters reached 62.3 mm (+1.03 SE) and 66.9 mm (+1.36 SE) within 18 months from spawn and that survival ranged from 64.5% to 70.6%. Enterprise budget estimated that for every 250,000 in oyster sales would provide $177,000 of economic impact and that farms would reach profitability in three to five years. A survey of restaurants in five cities, Savannah, Athens, Atlanta, Macon and Augusta found strong demand for Georgia grown oysters and that demand is higher than supply and favorable to direct shipping. Direct shipment of oysters by growers found that shipment is an efficient way to send small batches of oysters inland.  Overnight shipment in Styrafoam coolers performed best and receiving temperature of oysters was correlated with outside air temperature (R²=0.6894). This data indicates that oyster aquaculture on intertidal leases is possible and that there is a market for Georgia oysters throughout the state. With recent changes to the Georgia Code regulating shellfish aquaculture, that took effect in 2020, we are optimistic that there will be growth of the oyster aquaculture in Georgia.

Background and Objectives

The world population is estimated to exceed nine billion people by the middle of the 21st century and growth in aquaculture production is an important component to meet the growing demand for food. Aquaculture production continues to increase and is projected to exceed wild capture production by 2030 (FAO 2018).  From 2000 through 2016, aquaculture production increased from 32.4 million tons to 80.3 million tons while wild capture production has decreased slightly (from 93.5 to 90.9 million tons) over the same period (FAO 2018). In 2016, consumption of seafood in the U.S. was 16 pounds per person with 5.8 pounds estimated to be from shellfish; oyster production reached 36.6 million pounds with a value of $192 million during the same period (NMFS 2020).

The eastern oyster (Crassostrea virginica) is an important aquaculture species and demand for them has increased steadily. Over the past decade, commercial oyster harvest along Atlantic coast states has increased from 2.8 million pounds in 2008 to 6.8 million pounds in 2017 with an increase in value from $24.1 million to $111.0 million (NOAA 2020). Over the same time period, Georgia has seen a minimal increase in harvest from 15,496 to 28,755 pounds and value of $65,775 to $178,133. This lags behind other south Atlantic states such as North Carolina and South Carolina that have stable harvest from aquaculture and harvested 318,602 and 326,833 pounds with a value of 5.58 million and 2.61 million in 2017, respectively (NOAA 2020).

The low harvest rate in Georgia’s oyster industry is because it is built upon the manual harvest of wild oysters, which is labor intensive because of how the oysters grow. Wild oysters are crowded on dense reefs in the intertidal zone, which makes growing a naturally consistent shape, developing a deep cup, and separating oysters from one another difficult.  Although wild-produced cluster oysters are perfect for oyster roasts, they are less valuable than farmed oysters grown in aquaculture operations, which use hatchery-produced seed. Farmed oysters grow with a consistent appearance that is desired by restaurants and oyster bars and command a higher price (Bliss and Walker 2012).  The wild-caught oyster industry in Georgia is unequipped to compete commercially and would benefit financially by utilizing oyster aquaculture gear to become a viable industry.  Georgia’s moderate climate, tidal conditions, salt marsh productivity, and abundance of phytoplankton are ideal conditions for oyster growth.

Starting March 2020, two types of shellfish leases are available within Georgia, intertidal water bottom and sub-tidal water bottom.  The benefits from farming with floating gear in water column are well known, but leases within Georgia are dominated by intertidal leases that cover approximately 150,000 acres which only allow use of bottom gear.  Farming oysters to harvest size in bottom cages is challenging, and the risk of fouling (Moroney and Walker 1999) or suffocation by shifting sediments (Adams et al. 1994) are concerns that must be addressed.

In addition to environmental concerns with oyster harvest, distribution of market-size oysters to restaurants by growers can be difficult. Chefs with individually managed mid to high-end restaurants (IMMHERs) in urban Atlanta and Athens are enthusiastic about and eager to obtain fresh Georgia oysters (Yandle and Tookes 2016).  Distribution of oysters is challenging, as logistics companies typically deal in larger volumes of product than small growers are able to produce, and oysters are a seasonal product in Georgia. There is also interest in oysters from 90% of Georgia seafood consumers purchasing Georgia seafood at local farmers markets, but Georgia seafood is often overlooked and under represented at farmers markets (Tookes et al. 2018). Within Georgia, lease holders that obtain a Master Harvester Permit (MHP) are allowed to sell oysters directly to end users.

In 2017, it was estimated $69.6 billion of dollars spent on seafood occurred in restaurants (Love et al. 2020).  With the onset of COVID-19 (SARS-CoV-2) in 2020, the economy of the US and the world shifted. It is estimated that 17% of all restaurants in the U.S. have closed (National Restaurant Association, 2020). Since the outbreak, there has been 65% reduction in seafood demand within the U.S (White et al. 2020).  This led to an extension being granted to allow restaurant surveys in the five urban areas to capture some of the impact to IMMHERs in Georgia during the Covid-19 pandemic.

Therefore, this project focused on four key objectives to oyster farming in Georgia:  1) evaluate use of on-bottom growing techniques for oyster growth and survival to harvestable size on intertidal leases, 2) survey IMMHERs in five urban areas within Georgia, 3) evaluate the feasibility of direct-to-end user distribution methods via ground and overnight shipping, and 4) develop a budget tool to determine if on-bottom oyster farming will be economically viable and profitable.