Scientists Search for Best Way to Restore Oysters in Chesapeake Bay

By Acacia Coronado | Photographs by Greg Kahn for The Wall Street Journal

Scientists are racing to stem a rapid decline in the oyster population in Chesapeake Bay.

The number of oysters, a valuable part of the shellfish industry in the region, has fluctuated and been unreliable since the 1980s. The amount of market-size mollusks harvested in the Maryland stretch of the bay fell from about 380,000 bushels in the 2015-16 season to 180,000 bushels in the 2017-18 season, according to state data.

Water pollution, parasites and overfishing are among the reasons behind the decline, scientists say. Also, heavy rains can increase the flow of fresh water into bays, lowering water salinity and making it uninhabitable for oysters.

"The current population baywide of oysters is estimated to only be a couple percent of what were here in colonial times," said Will Baker, president of the advocacy group Chesapeake Bay Foundation, citing recent studies.

The Chesapeake Bay Foundation is one of several local, state and national organizations working to restore oyster populations in the area. One of its goals is to replenish oysters to the bay by placing hatchery-produced seed oysters in sanctuary reefs.

About 32 million pounds of U.S. oysters worth more than $236.4 million were harvested in 2017, a decrease of nearly 1.5 million pounds from the previous year, according to the National Oceanic and Atmospheric Administration. About 15% of the 2017 haul was from the Middle Atlantic region, which includes the Chesapeake Bay.

In addition to the shellfish industry, oysters are essential to the estuary ecosystems in which they live because they filter water, removing excess algae and converting it to food. Oyster reefs also are a magnet for a variety of other marine species.

The Sustainable Oyster Population and Fishery Act of 2016 required Maryland's Department of Natural Resources, in partnership with the University of Maryland, to conduct a study and adopt a new oyster management plan by 2018.

Dr. Michael Wilberg, professor at the University of Maryland Center for Environmental Science and an author of the state's 2018 oyster stock assessment, said oyster populations tend to oscillate. In addition to disease, contamination and harvesting, the rate of oyster reproduction varies. For example, oyster populations recovered after a dramatic hit from disease in the early 2000s.

The current population and habitat monitoring process costs more than $7,000 a day and requires sending a professional diver into dangerous underwater territory, which limits the amount of reefs that can be assessed. Scientists said because of the time and monetary cost of getting information, they are unable to consistently track data from every section of oyster habitat.

"Getting information from that system is very challenging because we are not underwater creatures," said Allison Colden, Maryland fisheries scientist with the foundation.

The foundation is working with global aerospace and defense-technology firm Northrop Grumman Corp. to develop new remote-sensing technology to track oyster populations and the health of oyster reefs in the bay. The new process will include capturing underwater imagery, mapping the reefs and collecting water chemistry -- without underwater divers.

R. Eric Reinke, chief science officer at Northrop Grumman, said six teams within the company are competing to come up with the best new technology, with the goal to start testing in early 2020. The company, which is based in the Baltimore area, has partnered on environmental education and preservation efforts for about 15 years.

"We're here to help the CBF reach its goal of planting 10 billion new oysters by 2025," Mr. Reinke said. "We have thousands of employees in the state of Maryland and consider the Chesapeake Bay part of our backyard."

Restoration efforts in the past 20 years have included placing oyster shells into habitats where new oysters can use them to grow and building concrete columns that reinforce oyster reef structures, said Doug Myers, senior scientist in Maryland for the Chesapeake Bay Foundation.

Ms. Colden said once the new technology is ready, one main goal is to use it to assess what techniques have worked effectively and to identify which locations in Maryland and Virginia need the most work.

"This is not a short-term goal, restoring oysters in the Chesapeake Bay will take a while," Ms. Colden said.

(END) Dow Jones Newswires

August 03, 2019 07:44 ET (11:44 GMT)

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