Folks who are regulars at oyster roasts in the area know there’s something special about oysters from the Nansemond River. Plump, juicy and loaded with flavor, Suffolk’s oysters are a local favorite.

Most of those folks also know, however, just how rare it is to find true Nansemond River oysters, even at the oyster roasts that take place right here in Suffolk. Sometimes those oysters come from other parts of the Chesapeake Bay, and sometimes they come from as far away as the Gulf Coast.

Virginia’s native oyster, Crassostrea virginica, has seen hard times during the past half-century or so. According to the Agricultural Marketing Resource Center, during the middle part of the 20th century, oyster production in Virginia reached four million bushels a year, with many of those coming from the Nansemond and the other rivers in Hampton Roads that drain into the Chesapeake Bay. In 1960, according to the Virginia Marine Resources Commission, Virginia produced 30 percent of the nation’s supply of oysters.

But overfishing in the Bay and its tributaries — combined with a couple of devastating diseases, the general decline of water quality in the oysters’ habitat and flooding from Hurricane Agnes — had a cumulatively catastrophic effect on the population of native oysters. By the year 2001, harvests in Virginia had dropped to just 23,000 bushels, with effectively none coming from the Nansemond River, whose history for generations had been intertwined with that of Crassostrea virginica.

And it wasn’t just a history of using oysters for food — it was a history of relying on them to help clean the Chesapeake Bay. Experts say that when John Smith arrived in North America, the oyster population could filter the entire bay in one week. Four hundred years later, it takes an entire year for that to happen.

But things are looking better for Virginia’s oyster industry. In 2011, 236,000 bushels of oysters were harvested from state waters. A variety of measures have contributed to the rebound.

Among those measures have been the efforts by various organizations to plant and cultivate oyster beds. Right here in Suffolk, the Nansemond River Preservation Alliance has taken the lead in the oyster farming effort. With the help of students from schools in Suffolk and Isle of Wight, the organization has planted 35,000 oysters in the Nansemond River and Chuckatuck Creek.

Students delivered the oysters to two sites by boat during field trips and the alliance’s River and Creek Fest at Bennett’s Creek Park on June 2. They had raised the baby oysters since October in floats tethered to docks and other structures.

The effort has the dual benefit of giving students hands-on experience with scientific discovery and of replenishing a resource whose loss would have meant far worse than the end of area oyster roasts.