Eastern Oyster
Eastern Oyster
Crassostrea virginica
Also Known As
American oyster, Atlantic oyster, American cupped oyster, Virginia oyster
Quick Facts
Length
Average 3 to 5 inches in length; can grow up to 8 inches
Lifespan
Up to 20 years
Threats
Disease, Degraded Water Quality, Habitat Loss, Overharvesting, Changing Conditions Due to Climate Change
Region
New England/Mid-Atlantic,
Southeast
Oysters cultured along the Gulf coast using off-bottom methods. Credit: Scott Rikard, Auburn University Shellfish Laboratory
Oysters cultured along the Gulf coast using off-bottom methods. Credit: Scott Rikard, Auburn University Shellfish Laboratory
About the Species
The Eastern oyster is treasured as food by humans and other species. They are habitat for fish, crabs, and other aquatic life—and because as filter feeders, they help filter the water. Centuries ago, they were plentiful. In some places, reefs were so big that ships had to navigate around them. Since then, in many areas, the populations have dwindled to just a few percent of what they once were. This is due to disease, overharvesting, habitat loss, and poor water quality.
But people, including NOAA scientists, are working hard to rebuild oyster populations. Many people are growing oysters for people to eat. Oyster aquaculture—farming of these tasty shellfish—is a growing industry. And NOAA and our partners are working to restore the healthy oyster reefs that so many other species rely on for habitat. Recreational anglers target healthy reefs for fishing opportunities, too. In the Chesapeake Bay, for example, NOAA and partners are involved in the world’s largest oyster restoration effort. There, they have restored nearly 1,400 acres of oyster reef—that's more than 2 square miles, or 1,055 football fields.
Appearance
At maturity, Eastern oysters can reach up to 8 inches. The shell has smooth edges and is oval with a "cupped" shape, giving rise to its alternate name "American cupped oyster." The inside of the shell is white to off-white to brownish in color.
Biology
Eastern oysters are of the shellfish family. Like mussels, clams and scallops they are bivalve mollusks, and have a hinged shell. They have fast growth rates and high reproduction rates. Each female Eastern oyster can product over 100 million eggs during one spawning event.
Adult Eastern oysters are sessile—they stay in one place—and inhabit both intertidal and subtidal areas. They first mature as males, and then later develop female reproductive capabilities.
Where They Live
Range
Eastern oysters are found along eastern North America from the Gulf of St. Lawrence to the Gulf of America (formerly Gulf of Mexico). They are found in the middle and lower Chesapeake Bay and its rivers. They are the only species of oyster native to this region.
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.
Scientific Classification
Eastern oysters are found along eastern North America from the Gulf of St. Lawrence to the Gulf of America (formerly Gulf of Mexico). They are found in the middle and lower Chesapeake Bay and its rivers. They are the only species of oyster native to this region.
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.
Scientific Classification
| Kingdom | Animalia | Phylum | Mollusca | Class | Bivalvia | Order | Ostreida | Family | Ostreidae | Genus | Crassostrea | Species | virginica |
|---|
What We Do
Sustainable Fisheries Management
The wild oyster harvest is managed by individual states or other jurisdictions. Similarly, aquaculture permitting is run by states. Guidelines and procedures vary from state to state. In some areas, NOAA scientists collaborate with state and other resource managers. They provide the most up-to-date science to help the resource managers make decisions and set regulations.
Science
NOAA supports science that resource managers and decision makers can use as they set regulations about wild oyster harvest and aquaculture operations. NOAA science also helps practitioners who are restoring oyster reefs learn about the best ways to make their work effective and efficient.
Featured News
Brenden Doyle, the founder and owner of The Great Marsh Shellfish Company, grows oysters in the largest contiguous salt marsh in New England. Credit: The Great Marsh Shellfish Company
Feature Story
Meet The Great Marsh Shellfish Company, Oyster Growers in Massachusetts
New England/Mid-Atlantic
Tal Petty is an oyster farmer in Hollywood, Maryland. Credit: Hollywood Oyster Company
Celebrate Culinary Arts Month with a sustainable seafood recipe for every month of the year.
Feature Story
What Your Birth Month Says About Your Next Seafood Recipe
Alaska
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
Stevens Towing building new oyster sanctuary reefs in the Pamlico Sound, North Carolina. Credit: Stevens Towing.
Feature Story
Oyster Restoration Investments Net Positive Returns for Economy and Environment
Southeast
Related Species
Seafood Facts
Are Eastern Oysters Sustainable?
U.S. farmed Eastern oysters are a smart seafood choice because they are sustainably grown and harvested under U.S. state and federal regulations.
Availability
Year-round.
Source
Estuaries, mainly the East Coast or Gulf of America (formerly Gulf of Mexico).
Taste
Ranges from sweet to briny.
Health Benefits
Oysters are low in saturated fat and excellent sources of omega-3 fatty acids, iron, and zinc.
Nutrition Facts
Servings: 1; Serving Weight: n/a; Calories: 81; Protein: 9.45 g; Total Fat: 2.3 g; Total Saturated Fatty Acids: 0.5 g; Carbohydrate: 0 g; Total Sugars: 0 g; Total Dietary Fiber: 0 g; Cholesterol: 50 mg; Selenium: 77 mcg; Sodium: 106 mg; Zinc: 16.62 mgOyster Recipes
Looking for some ways to add oysters into your rotation? If you need some cooking inspiration, browse these recipes for bourbon grilled oysters, bacon-wrapped oysters, and more!
Seafood News
Credit: Howard Stanbury (left); NOAA Library/NOAA Fisheries circa 1939 (right); NOAA (background)
Feature Story
New England Fishery Management: Backed by Science, Shaped by People
New England/Mid-Atlantic
National
U.S. Senators Ted Stevens (R-AK) and Warren Magnuson (D-WA), 1973.
Leadership Message
50 Years of Innovation and Leadership: Celebrating the Magnuson-Stevens Act
Alaska
New England/Mid-Atlantic
Pacific Islands
Southeast
West Coast
National
International
Danielle Blacklock, Director of NOAA Fisheries Office of Aquaculture, eating an oyster on the half shell. Credit: NOAA Fisheries.
Oyster Management and Restoration
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.
But their status as a tasty source of protein, vitamins, and minerals led to years of overharvesting. Oysters also face challenges from disease and habitat degradation. Today, in many areas, oyster populations are only a fraction of what they once were. In the Chesapeake Bay, scientists estimate that the population is only at 1 to 2 percent of historic levels.
Image
NOAA is teaming up with other organizations to restore oyster reefs up and down the East Coast. In the Chesapeake Bay, we are part of the world’s largest oyster restoration effort. With partners, we are working to restore oyster reefs in 10 Chesapeake Bay tributaries by 2025. That’s the goal set by Chesapeake Bay Program. So far, three tributaries are considered restored, and work continues in seven more. All together, in Maryland and Virginia, roughly 1,100 acres can be considered restored as part of this effort.
We also support science related to Eastern oysters. Our scientists provide technical advice to people who are working on oyster restoration projects. And we carry out and fund research about oysters, too. A 2021 report details the benefits that restored oyster reefs bring to the ecosystem, such as:
- Filtering the water
- Providing habitat for fish, crabs, invertebrates, and other macrofauna
- Supporting commercial and recreational fishing
Aquaculture
Eastern oyster aquaculture is carefully managed and monitored under federal, state, and local regulations to protect ecosystems and ensure shellfish are safe for human consumption. Oyster aquaculture can provide environmental benefits by improving water quality, requiring no feed, and using a range of sustainable farming methods.
Environmental Impact
Oysters provide net environmental benefits by removing excess nutrients and improving water quality.
Feeds
Growing oysters requires no feed—they filter phytoplankton directly from the water column.
Farming Methods
Oysters are grown in tidal areas. They can be grown directly on the beach bottom or in mesh bags, trays, or cages that are either anchored in the water column or floated on rafts.
Human Health
Shellfish toxins and bacteria occur naturally in the environment and can cause foodborne illnesses. State and federal regulations require monitoring of farmed oysters to ensure they are safe to eat.
Management
Permitting for shellfish aquaculture is governed by federal, state and local governments. The federal agencies involved in the authorization or permitting of aquaculture in the U.S. include NOAA, the U.S. Army Corps of Engineers, U.S. Fish & Wildlife Service, U.S. Department of Agriculture, the Environmental Protection Agency, the Food & Drug Administration, and the U.S. Coast Guard.
All fisheries and aquaculture farms must adhere to federal regulations including those in the Magnuson-Stevens Act, the Endangered Species Act, the National Environmental Policy Act, the Clean Water Act, and the Marine Mammal Protection Act.
Information on shellfish aquaculture permitting can be found in the Shellfish Growers Guide (PDF, 10 pages). A variety of shellfish aquaculture tools, including maps and models, are also available to coastal managers.
Farming Methods
Image
Juvenile Oyster (Seed) Production
Oyster larvae are raised in hatcheries and fed algae. After about two to three weeks, the larvae settle out of the water column and attach to a surface, typically crushed or whole aged oyster shells. These settled larvae, now called spat, are then cultured in tanks for a few weeks before being moved to grow-out sites on farms.
Oyster Grow-Out
Pacific oysters are sustainably grown and harvested in tidal areas. They can be grown directly on the beach bottom or in mesh bags, trays or cages that are either anchored in the water column or floated on rafts.
- On-bottom Culture: Oyster spat are spread directly onto the bottom substrate of intertidal areas.
- Off-bottom Culture: Oyster spat are placed in bags on racks, or in cages or hung on long lines attached to anchored frames or poles in the intertidal zone.
- Suspended Culture: Bags or cages are attached to rafts or floats.
Production
In 2022, the United States produced 29.7 million pounds of oysters (both Eastern and Pacific oysters), valued at $199 million.
Environmental Considerations
Habitat
Oyster farming has a benign ecological footprint, with little disturbance of sediments or aquatic vegetation during grow-out. Some oyster harvesting methods involve dredging, but long-term effects on the environment are rare.
Feeds
Once past the larval stage in the hatchery, oysters do not need to be fed because they filter their food from the water column.
Genetics
The Eastern oyster is grown in its native range, so there is some concern that farmed oysters could decrease genetic variability of wild populations. However, this has not been an issue in the United States.
Ecosystem Services
Aquaculture farms can provide a wide range of benefits, from creating habitat for fish and crustaceans to helping improve water quality around farm sites. These benefits are referred to as ecosystem services.
Water Quality
Image
Oysters are filter-feeders, removing algae, organic matter, and excess nutrients from the water column as they grow and improving water quality for other species. When oysters are harvested, nutrients such as nitrogen and phosphorus are removed from the ecosystem.
Providing Habitat
Oysters and the gear used to farm oysters can provide habitat for other marine organisms. Oyster beds also stabilize coastal sediments and help minimize impacts from storm surges.
Human Health
Shellfish Toxins
Shellfish poisoning is an illness that can occur from eating contaminated shellfish.
Shellfish can assimilate the toxins causing shellfish poisoning from the algae on which they feed. Early warning systems exist to detect harmful algal blooms that produce toxins.
New technologies, such as the Environmental Sample Processor, provide near real-time detection of harmful algal species.
NOAA's Harmful Algal Bloom Forecasting Program
Pathogenic Bacteria
The bacteria Vibrio parahaemolyticus (Vp) occur naturally in the environment and can cause foodborne illness from consuming raw shellfish or undercooked shellfish that has Vp bacteria can lead to gastrointestinal illness.
Public health officials monitor shellfish farms, harvests, and the surrounding area to ensure they are safe to eat from biotoxins, bacteria and viruses.
Science Overview
Overview
NOAA fisheries conducts various research activities on the biology, behavior, and population health of Eastern oysters. The results of this research are used to inform management decisions for this species.
Researching Farmed Eastern Oysters
Growth and Reproduction
In 2024, the Northeast Fisheries Science Center’s Milford Lab and the U.S. Department of Agriculture's Agricultural Research Service launched a state-of-the-art Northeast Oyster Breeding Center. The center is an investment that is bolstering shellfish farming in the Northeast.
Scientists are using advanced selective breeding methods to develop better-performing lines of Eastern oysters to boost production. They aim to breed disease-resistant oysters that are resilient in the face of current and changing environmental conditions in the Northeast’s diverse oyster growing areas.
Ocean Acidification
Ocean acidification—caused by increased carbon dioxide absorption into the ocean—can cause a number of changes in water chemistry that may be stressful to oysters and other shellfish by hindering their ability to build and maintain their shellsestuarine organisms like oysters. NOAA and our partners are actively researching these effects and exploring potential solutions. investigating ocean acidification and its impacts on shellfish. For more information, visit NOAA’s Ocean Acidification Program.
Ecosystem Services
Oyster farms can provide a wide range of benefits, from creating habitat for fish and crustaceans to helping improve water quality around farm sites. These benefits are referred to as ecosystem services.
The Northeast Fisheries Science Center’s Milford Lab’s GoPro Aquaculture Project is using camera footage to understand interactions between shellfish aquaculture gear and wild fish communities. To date, they've observed 21 species of fish in their videos associating and interacting with oyster cages.
