Maryland Oyster Survival Rate Highest Since 1985


Governor proposes $8 million capital investment for oyster restoration

Oyster disease levels lowest on record

 ANNAPOLIS, MD (February 13, 2012) – Governor Martin O’Malley today announced another landmark in the State’s ongoing efforts to restore the Chesapeake Bay’s native oyster population. Results of Maryland’s 2011 Fall Oyster Survey show the highest survival rate for oysters since 1985.  The 92 percent survival rate — the percentage of oysters found alive in a sample — builds upon last year’s strong spatset (number of baby oysters), which was the highest since 1997.

“Although our fight to restore a thriving oyster population to the Chesapeake Bay is far from over, our continued commitment to renewing this iconic species has begun to pay off,” said Governor Martin O’Malley. “Through balanced investments in aquaculture, sanctuaries, stewardship and enforcement, our native oyster is coming back. Together, we can continue to create jobs and support our local economies while returning our native oyster to healthy, sustainable levels.”

In one of the longest running resource-monitoring programs in the world, the Maryland Department of Natural Resources (DNR) and its predecessor agencies have monitored the status of the State’s oyster population via annual field surveys since 1939.  The survey tracks reproduction levels, disease levels and annual mortality rates, and offers a window into future population levels.

“The high survival of young oysters from 2010’s record spatset is an immediate asset to Maryland’s expanded sanctuary program,” said DNR Secretary John Griffin. “As these oysters grow and reproduce, they are supporting expanded populations in sanctuaries, public fishery areas and aquaculture operations.”

In his proposed FY2013 budget, Governor O’Malley has proposed a $7.5 million capital investment in oyster bar restoration in Harris Creek in Talbot County and the Little Choptank River in Dorchester County, two of the State’s new sanctuaries, where conditions are favorable for reproduction. The Governor has also proposed an additional $500,000 for aquaculture infrastructure improvements, which will include low-cost loans through the Maryland Agricultural and Resource Based Industry Development Corporation (MARBDICO) for entrepreneurial watermen and other citizens who want to grow oysters.

During the 2-month sampling assessment, which concluded on November 21, 263 oyster bars and 343 samples throughout the Bay and its tributaries were evaluated.  Analyses of disease samples and field data were completed this month.

“This is more than double the survival rate in 2002, when record disease levels killed off 58 percent of the population,” explained DNR Fisheries Service Director Tom O’Connell. “The overall biomass index — which measures population health by volume — is also up 44 percent over last year.  Not only did these baby oysters thrive under ideal growing conditions, this year we also found a new, high spatset in high salinity areas such as the Tangier Sound.”

In another positive sign, scientists at the Cooperative Oxford Laboratory report that the frequency and intensity of diseases are low.  Of the two diseases that have devastated populations for decades, Dermo, although still common, now occurs at the lowest level on record and remains well below the long-term average for the eighth consecutive year.  MSX is also at its lowest level on record.

Although high freshwater flows from heavy rains in the spring and  late summer storms – Hurricane Irene and Tropical Storm Lee — impacted oysters above the Bay Bridge, this represented a relatively small proportion of the total oyster population. The lower salinities proved to be beneficial to the majority of oysters in Maryland by knocking back disease.

“These reductions in MSX and dermo diseases in Maryland oysters are promising, providing favorable circumstances for expanding aquaculture, increasing restoration efforts, and strengthening initiatives to protect and conserve our wild populations,” said Chris Dungan, manager of oyster disease research at the Cooperative Oxford Lab.

Since 1994, the Chesapeake Bay oyster population has languished at less than one percent of historic levels. Over the past 25 years, the amount of suitable oyster habitat has declined by 80 percent — from 200,000 acres to just 36,000 acres. Maryland’s annual oyster harvest has fallen from an average of 2.5 million bushels in the late 1960s to about 105,000 bushels a year since 2002, while the number of oystermen working Maryland’s portion of the Bay has dwindled from more than 2000 to just 550.

In 2009, the State of Maryland adopted regulations to implement Governor O’Malley’s Oyster Restoration and Aquaculture Development Plan. The plan increased Maryland’s network of oyster sanctuaries from 9 percent to 24 percent of remaining quality habitat; increased areas open to leasing for oyster aquaculture and streamlined the permitting process; established a $2.2 million financial assistance program for aquaculture interests; and maintained 76 percent of the Bay’s remaining quality oyster habitat for a more targeted, sustainable, and scientifically managed public oyster fishery. The plan also focused on stepping up enforcement to protect the State’s investment in the oyster population.

Since the 2010 implementation of the Governor’s Oyster Recovery Plan, 28 new oyster farming leases have been approved for more than 20 individuals on about 650 acres.  More than half of these entrepreneurs are watermen.  An additional 52 lease applications covering 620 acres are currently being processed.



Marylanders Grow Oysters Regarding your cage oysters, two points to make are:

– Any future drought will have less of an impact on the cage oysters because we selected sanctuary planting sites in areas with good survival even in most drought conditions; to build in a biological cushion for your oysters. Also, your piers are located in areas where disease effects have historically been low, for most of you.

– On the improved survival news, oysters from your cages will benefit in that the sanctuary sites where your oysters are planted are also under this positive influence of low salinity.

– However the recent heavy rains are a mixed bag: the oysters in your cages first have to survive so they can be planted in these beneficial sanctuaries. And since many cages are upstream in the rivers and creeks, it happens that the high amounts of rain, in some cases not all, have caused mortality due to salinities that are too low for the oysters. You may have noticed a die off in your cages if you are in a low salinity susceptible area. But then again, if you are in an area not so heavily affected by rain, your cages are ok.

Basically, it depends where you are.

So, overall oysters are doing better , but perhaps your oysters have experienced some level of mortality due to fresher waters. As the weather warms up in the next two months, you will soon see your spat grow and can then estimate how well they have come through the heavy rains of 2011. Let me know if I can help.