History of oysters

The rise and fall of a key Chesapeake Bay species

Oysters have a longstanding history in Chesapeake Bay. In the early 17th century, Capt. John Smith described oysters lying “as thick as stones.” Elizabeth North, an oyster scientist at Horn Point Laboratory, said they had been so abundant that their reefs neared the water’s surface, sometimes becoming navigational hazards.

At the end of the 19th century, it was estimated that more than 15 million bushels of oysters were being harvested annually from the Maryland portion of the Bay. By 2011, the oyster population in the upper Chesapeake Bay was estimated to be 0.3 percent of population levels of early 1800s due to overfishing, habitat loss, and disease, according to a study led by Mike Wilberg, a fisheries scientist with the Chesapeake Biological Laboratory.

Overharvesting oysters did more than deplete the resource. Every time an oyster leaves the water, a piece of the habitat oysters and other Bay species need is also lost. Between 1980 and the time of the study three decades later, suitable habitat declined about 70 percent. The number of oysters were already falling rapidly by this time due to two diseases, Dermo and MSX, which started spreading through the Bay in the late 1950s and early 1960s.

“The collapse of eastern oysters in Maryland waters of Chesapeake Bay is among the largest documented declines of a marine species,” Wilberg said at the time, later adding, “Maryland has made positive steps toward conserving oysters by increasing the area that is off limits to fishing and increasing support for aquaculture.”

Reginald V. Truitt, the man who would plant the seeds for what would become the University of Maryland Center for Environmental Science, was committed to understanding the cause of oyster decline in Chesapeake Bay when he opened Chesapeake Biological Laboratory in Solomons in 1925. Truitt was among the first to realize the Bay’s growing decline—and its potential for renewal with the assistance from humankind.

The continued diminishment of oyster numbers even decades later inspired a partnership of several organizations that would each use their strength to contribute to an overall effort to restore oyster populations in Chesapeake Bay. In the summer of 1993, the state of Maryland brought together a panel of 40 experts made up of elected officials, organizations, and institutions like University of Maryland Center for Environmental Science. This was the Oyster Roundtable, and its members’ mission was to address the troubled oyster population in Chesapeake Bay. Diseases, harvesting, and poor water quality were devastating the Chesapeake Bay oyster, a key species that dated back centuries.

That December they released a 30-page Action Plan for Oyster Recovery. The action plan detailed a series of critical next steps and laid the foundation for the restoration program now underway at Horn Point Laboratory’s oyster culture facility and elsewhere in UMCES and the founding of the Oyster Recovery Partnership in 1994. Restoration partners include the Maryland Department of Natural Resources, the Chesapeake Bay Foundation, the National Oceanic and Atmospheric Administration, and U.S. Army Corps of Engineers.

Today, the Broddus and Margaret Ann Jones Oyster Culture Facility at Horn Point Laboratory, one of the essential partners, produces hundreds of billions of spat annually with the vast majority placed on sanctuary reefs that serve as broodstock for the entire population.

In 2018, UMCES led a science-based stock assessment for oysters in Maryland's portion of Chesapeake Bay in 135 years. “Our job was to give the best scientific estimates of the current status of the population to help inform future management decisions,” said Wilberg. Read the Oyster Stock Asssessment.

The collapse of eastern oysters in Maryland waters of Chesapeake Bay is among the largest documented declines of a marine species.

Mike Wilberg
Fisheries scientist, Chesapeake Biological Laboratory