Oysters filter nutrients and sediment from the water — the pollutants most responsible for the bay’s degraded condition. In the late 1800s, when commercial harvests topped 100 million bushels a year, the bivalves were so abundant that scientists estimate they could filter all the bay’s water in less than a week.
But overfishing, loss of reefs on which oysters can grow, and a pair of diseases, MSX and Dermo, have reduced the bay’s population to just 1 percent of historic levels. Harvests in recent years have fallen below 100,000 bushels, despite a replanting effort that has put hundreds of millions of hatchery-reared oysters in the bay.
Summary of a century’s change in the Chesapeake, from an item about reform of state strategy for oyster fishing & aquaculture in Saturday’s Sun.