The University of Maryland Center for Environmental Science’s (UMCES) Horn Point Laboratory (HPL) is probably best known for its oyster hatchery, which has been operating since 1974. The director of the oyster hatchery is Stephanie Alexander who has been working at the hatchery for 28 years and has been its director for six. There are 8 full-time employees and up to 20 interns starting in late spring.
Blue crabs may be the showmen of the Eastern Shore, but oysters are its lifeblood. Called the vacuum cleaners of the Chesapeake Bay, this keystone species can filter up to 50 gallons of water daily, cleaning the river and increasing the oxygen levels. Oyster reefs become homes for fish and other filter feeders like mussels and barnacles. Oysters clean the water by consuming algae and packaging the sediment into bundles which fall to the bottom of the riverbed. It takes two to three years for an oyster to reach adulthood.
Oysters are so critical to the bay that Horn Point Laboratory’s hatchery has increased its oyster production. In 2005 Horn Point Laboratory opened the new Aquaculture and Restoration Ecology Lab (AREL) and in 2011 it built a new Setting Pier. AREL is used for producing oyster larvae and the Setting Pier is where the oysters attach to a shell and become spat (spat are baby oysters that have attached and are no longer mobile).
The state-of-the-art facility produced 1.76 billion (yes, that’s billion!) oysters in 2023. Since many of the processes are now automated—including feeding, filtration, and water temperature—key components can be adjusted quickly to improve results. Equipment such as the Coulter Counter counts larvae, eggs, and algae particles. Auto-titration measures calcium carbonate in water. (Oysters need calcium carbonate to build their shells.)
The process for raising oysters begins with the moms and dads. The hatchery isolates these oysters and provides warm water to stimulate the production of eggs and sperm (both are referred to as gametes). The oyster parents feed on the nutrients from the Choptank river. The hatchery places the eggs in water containing sperm, and they are fertilized and become larvae. While larvae are mobile, they are placed in a tank and fed algae produced by the hatchery. After 14-20 days, the baby oysters (larvae) are placed in a tank filled with oyster shells. Within 48 hours they will have attached to the oyster shells and subsequently are given a few extra days for their shells to harden. Once they attach, they are called spat. After their shells have hardened, the spat are ready to be placed in restoration areas and sold to aquaculture.
The hatchery has four primary roles: restoration, aquaculture assistance, supporting research, and education.
Restoration of the bay and its tributaries is a key mission of the hatchery, and 75% of the oysters that it produces are used for restoration. Horn Point works with partner organizations putting diploid oyster spat into the bay. Through a partnership with the state, local government and federal agencies; Maryland Waterman’s Association; other hatcheries; scientists; and nonprofits (such as the Oyster Recovery Project); over thirteen billion spat have been placed in the bay and its tributaries. The newest bodies of water that will be targeted for oyster replenishment are the Nanticoke River, Heron Bay, Cooper Strait, and the Eastern Bay.
There are two primary strains of oysters, diploid and triploid. A diploid oyster has two sets of chromosomes, and a triploid oyster has three sets. Triploid oysters are essentially sterile while diploid oysters reproduce naturally. Since triploid oysters are not expending energy on reproduction, they tend to grow larger and faster. For obvious reasons, diploids are used for restoration work. Aquaculture frequently utilizes triploids because of their rapid growth.
The Horn Point hatchery provides 25% of its oysters to the aquaculture industry, including spat, seed, and larvae. Aquaculture businesses can purchase several strains of larvae (diploid and triploid), seed, and spat on shell.
Horn Point Laboratory works closely with its aquaculture customers. Through a Demonstration Oyster Farm at UMCES, new and existing aquaculture growers can learn grow-out and management techniques. In collaboration with partners including the Maryland Seafood Cooperative and Oyster Recovery Partnership, they provide a Remote Setting Training Program for setting larvae and aquaculture.
The hatchery also supports research. Research projects include studying the causes of hatchery crashes, evaluating oyster reefs and castles in living shorelines, and making oysters more resistant to stress. For the latter project, scientists are adding stressors to baby oysters to determine if that will make them more resilient. Other research projects focus on algae production (which feeds the larvae), water recirculation in tanks, and measuring oyster feeding and respiration rates.
It is clear that Alexander’s passion is education, she loves connecting with children and letting them see that even small actions can make a difference.
According to Alexander, one example of an action that we can take is recycling oyster shells. The bay is suffering from the lack of oyster shells The Oyster Recovery Partnership has a list of restaurants that participate in oyster shell recycling and a map of local recycling centers where individuals can take oyster shells to be recycled. There is work to be done, in Talbot County there are only three restaurants that participate in oyster shell recycling.
While enormously successful, the hatchery is not without its challenges. One challenge is funding. The director depends on grants and funding to keep the hatchery running. Any system upgrades await future funding.
But Alexander’s greatest challenge in the oyster hatchery? Good old Mother Nature. Since they use water from the Choptank, the variation in salinity, temperature, PH, and issues with algae blooms must be managed regularly. Mother Nature fluctuates, every year is different, and the hatchery (and aquaculture) must adapt.
Because of its emphasis on education, the hatchery provides many opportunities for us to see it in operation. The hatchery is open to tours throughout the summer months, and Horn Point Laboratory hosts an open house in October. Campus tours, which include the oyster hatchery, are offered weekly from Memorial Day to Labor Day.
For more information about Horn Point Laboratory, contact Claire Otterbein at [email protected]
Angela Rieck, a Caroline County native, received her PhD in Mathematical Psychology from the University of Maryland and worked as a scientist at Bell Labs, and other high-tech companies in New Jersey before retiring as a corporate executive. Angela and her dogs divide their time between St Michaels and Key West Florida. Her daughter lives and works in New York City.
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