(NPR) — A single freshwater mussel can filter more than 15 gallons of water in a day. They're “like nature's Brita filter,” a conservation biologist says.
But in one Virginia river, hundreds of thousands are believed to have perished.
A mysterious die-off of freshwater mussels has scientists scrambling to find a cause. Freshwater mussels clean water and provide habitat to countless other species.
The pheasantshell is a freshwater mussel, a less-edible version of its saltwater cousin that spends most of its inconspicuous life part-buried in riverbeds, blending in with the rocks and filtering the water around them.
In recent years, though, biologists and fishermen noticed something was wrong. On sections of the Clinch and other waterways in the Pacific Northwest and Midwest, dead mussels were turning up on shores and could be seen glinting from the river bottom. Surveys revealed more recently dead or dying mussels half-buried and rotting in still-clasped shells.