A Historic Year for Maryland Oysters

Gov. Wes Moore has announced a historic year for oyster reproduction in Maryland waters.

According to the Maryland Department of Natural Resources, the concentration of new oysters in 2025 was nearly six times higher than the long-term spatset average and the second highest ever recorded in the 41-year modern history of the state’s annual fall oyster survey.

“Oysters are the bedrock of the ecosystem in the Chesapeake Bay and provide economic opportunities for communities throughout the state,” Gov. Moore said. “Maryland is now seeing the best news for our oysters in decades; our robust and growing oyster population will help make sure we pass our Bay along to future generations as an heirloom—both as an economic driver for our seafood industry and for the environmental health of our waterways.”

The survey results are a milestone in the recovery of the Chesapeake Bay’s oysters, which are crucial to the health of the Bay and an important economic resource. Preliminary results indicate that the Maryland oyster population is growing throughout state waters at levels not seen in decades, while rates of mortality and disease remain low.

Major survey highlights include:

• At an index average of 250 spat (or juvenile oysters) per bushel at the key sites where scientists measure the intensity of spat, the survey measured reproductive success and potential population growth for oysters at the highest level recorded since 1997—more than three times higher than the prolific reproduction in 2023. The long-term spatset average is 42.2 spat per bushel.
• The survey found the second highest distribution of spat on record since 1985, lower only than 1991. Several areas saw especially high spatsets, including 3,600 spat per bushel on two bars in Broad Creek and more than 2,100 spat per bushel in the St. Marys River restoration sanctuary.
• Oyster mortality levels were the third lowest since 1985, continuing a dramatic decline in mortalities driven by low levels of oyster diseases. In 2025, presence and intensity of the disease Dermo were among the lowest in 36 years. Preliminary results also show very low prevalences of MSX, the other prominent oyster disease in the Bay.
• Maryland Department of Natural Resources shellfish biologists calculate that oyster biomass—the overall estimated weight of oysters in the local ecosystem—is at the highest in the 33 years since the department began estimating that value. Current biomass is more than five times higher than the lowest point in 2002, when oyster populations were devastated by disease.
• Available oyster habitat was also at the highest level, with the three-year average from 2025 tied with the highest in the 21 years the Maryland Department of Natural Resources has measured available hard-surface habitat.

Read more here.

The distribution of spat, or juvenile oysters, throughout the bay, with red representing the highest concentrations. Spat was found north of the Bay Bridge, and especially strong spatsets were found across the Eastern Shore and in sites on the western shores of the Bay.