The tropical storm that deluged Maryland in early September may have killed off many of the oysters in the upper Chesapeake Bay, a Department of Natural Resources spokesman said Monday.

DNR spokesman Josh Davidsburg wouldn't say how extensive or severe the die-off was, saying state biologists are still checking. But he did say preliminary reports indicate the bivalves died from an overwhelming influx of fresh water into the upper bay after Tropical Storm Lee, which rained 12 inches or more over much of the region.

Larry Simns, president of the Maryland Watermen's Association, said watermen have told him that 95 percent to 100 percent of the oysters are dead along the western Shore as far south as the Bay Bridge. The Chester River, Eastern Bay and other areas along the Eastern Shore were not hit as badly.

The storm dumped nearly 29 trillion gallons of rain on the mid-Atlantic region, by one estimate, flooding the upper bay with fresh water and flushing an estimated 4 million tons of sediment into it from the Susquehanna River alone. The dirt and debris turned the water a chocolate brown, and the surge of fresh water from rivers lowered salinity levels to near zero for weeks after the storm. Oysters don't grow or reproduce well in water with low salinity, and can even die if trapped in fresh water for weeks at a time.

Oysters farther down the bay appear not to have been greatly affected, if at all. Southern Maryland oyster grower Jon Farrington of Johnny Oyster Seed Co. said Saturday that salinity levels had dropped alarmingly in the lower Patuxent River after Hurricane Irene in late August, which produced locally intense rainfall. But the freshet did not last, and his oysters survived, he said.

tim.wheeler@baltsun.com

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