Washington ? Virginia scientists have discovered millions of native oysters thriving along shorelines in a section of the lower Chesapeake Bay once thought uninhabitable for them, a discovery that could shift efforts to revive the bay’s ailing oyster stocks.

The dense colonies of oysters analyzed this year in Virginia Beach’s Lynnhaven River suggest that, with the right habitat, the native species can clean the bay’s water and sustain annual harvests, according to a report to be released this month by the Virginia Institute of Marine Science.

Most remarkable, the scientists say, is evidence that oysters survive far better on riprap – manmade shoreline barriers built of granite boulders – than on many of the shell reefs researchers have developed for them. The finding is a breakthrough in a quest to replace oyster habitat that has consumed tens of millions of dollars over decades, with spotty success.

“It was serendipity hitting us in the face … in the last place one would normally think about restoring oyster brood stock,” said Rom Lipcius, a professor at the institute and author of the report. “Nature is showing us that there are alternative means for restoring native oysters. We have to grasp the opportunity.”

Overfishing and disease have left the bay’s Eastern oyster population at about 1 percent of what it was the dawn of the bay’s oyster industry a century ago. A decade-long restoration effort involving state and federal agencies, researchers and watermen has failed to raise those numbers substantially.