On Thursday, August 5, 2027, National Oyster Day celebrates a shellfish that can filter up to 50 gallons of water daily. That figure holds under ideal conditions, NOAA notes.
Oyster Day on the Calendar
August 5 is the date. Its timing may raise eyebrows, given the old rule about eating oysters only in months with an “r.”
The Chesapeake’s Oyster Boom and Bust
No founder of the food day is on record. America’s oyster story is easiest to trace in the Chesapeake Bay, where harvests were once enormous.
In the late 1880s, the bay was “the greatest oyster-producing region in the world,” a National Academies report says. Its fishery made up 39% of the entire U.S. oyster harvest.
Its catch was about twice that of the rest of the non-U.S. world. The bay also employed 20% of Americans who fished for a living.
Gear changed everything. Dredges were legalized in 1865. A worker with hand tongs might bring up 8 to 25 bushels a day, while patent tongs brought 30 to 100.
Dredging also broke apart the reefs themselves. By 1991, average oyster density had fallen to 4% of 1884 levels.
Disease piled on. MSX reached the lower bay from Delaware Bay by 1959. Dermo, first found in bay oysters in 1949, became a major killer in the mid-1980s.
Salinity shaped the damage. MSX, caused by the parasite Haplosporidium nelsoni, mostly spared oysters in water below 15 parts per thousand. Dermo, though, could kill them in fresher water over two or three years.
Why the “r” rule existed
Oysters were long skipped in months without an “r,” NOAA explains. After spawning, their quality was lower, and without refrigeration they spoiled.
Farming has changed that. Oysters raised in aquaculture can now be harvested in summer.
Reef Builders Worth Protecting
Each Chesapeake oyster works for the bay while it eats. It pumps water through its gills to catch plankton, trapping sediment and extra nutrients, and the reefs shelter young fish and crabs.
Restoration is underway at Harris Creek, on Maryland’s Eastern Shore. Crews built more than 350 acres of reef there starting in 2013, and a 2016 check found 97% met NOAA’s standards.
NOAA named the Choptank River complex, which includes Harris Creek, a Habitat Focus Area.
Harris Creek is a sanctuary, so its oysters stay off the menu. It was the first of 10 tributaries the Chesapeake Bay Program set out to restore by 2025.
Reefs are built from stone or shell, and oyster larvae settle on them to grow. NOAA checks the reefs every few years with sonar, divers and patent tongs.
Even so, the bay still has far to go. Its oyster population is only about 1% of what it once was, the agency says.
How to Mark National Oyster Day
- Order farm-raised oysters, since aquaculture beds can be harvested in summer.
- Ask restaurants whether they recycle shells, which are in short supply for reef building.
- Join an oyster gardening program, such as Marylanders Grow Oysters or the Chesapeake Bay Foundation’s.
- Cook them if you’re at higher risk, since the CDC says most vibriosis comes from raw or undercooked shellfish, especially oysters.
- Visit Harris Creek, the first tributary picked for the bay’s big reef restoration push.
Frequently Asked Questions
How common are Vibrio infections?
The CDC estimates about 80,000 U.S. cases a year, with roughly 52,000 tied to contaminated food.
When are Vibrio levels highest?
From May through October, when coastal water is warmer.
How fast could the old Chesapeake oysters filter the bay?
In about 3.3 days, by one 1988 estimate of the population at its peak before 1870.