A heaping shoal of oysters might have peeked above the water two centuries ago near what is now the Francis Scott Key Bridge. Such a shoal could explain why the U.S. Army built the hexagonal Fort Carroll in that same area in the late-1840s to defend the busy harbor.
But the shellfish have not thrived in the Patapsco River since.
It's difficult for them to reproduce there — the process requires saltier water and the population hasn't been able to withstand decades of industrial and urban pollution.
Now, Chesapeake Bay advocates are testing a strategy to give oysters a second chance in the Patapsco.
Shells carrying 3 million speck-sized baby oysters clattered off...