The United States exports $50 million in shells to Japan and buys $1 billion worth of pearls from that country.
December 18, 1998
Web posted at: 1:35 PM EST

By Hillary Mayell

(ENN) -- Planning on buying your beloved pearls for Christmas? Better do it now. While there have been a lot of press reports on the devastating effects caused by zebra mussels, the fact is that there are many species of mussel and according to mollusk specialists, mussels are the most endangered family of animals in the nation.

Nearly 70 mussel species are currently endangered, Richard Neves, a fisheries professor at Virginia Tech in Blacksburg, Va., says. The Nature Conservancy says two-thirds of freshwater mussels in North America are rare and imperiled.

From an economic point of view, the beads implanted in pearl oysters come from mussel shells harvested in the U.S. Ninety-five percent of the weight of a cultured pearl is from this bead. The United States exports $50 million in shells to Japan and buys $1 billion worth of pearls from that country.

At the ecosystem level, mussels are the longest lived of the freshwater invertebrates and have been filtering rivers for millennia. Besides serving as a natural biological filter, mussels are a food for fish and wildlife. Their presence is an indicator of good water quality. Today the mussel faces water quality degradation resulting from industrial and sewage effluents and the runoff of silt and other water pollutants from poorly designed construction, development, mining, agricultural, and forestry activities. Further, the spread of the exotic zebra mussel, which can out compete native mussels, is a threat.

They're pretty strange creatures. Mussels live on rocks and other hard objects and thrive off the coasts of Europe, America, and Southeast Asia in fresh and salt water. They have two hinged oblong shells that enclose soft bodies with no eyes or distinct head. Pea crabs live in their gills in a symbiotic relationship.

Sea lions and squid love them. The sea lion knocks a mussel against a rock until it cracks, and then eats the fragile body. The squid injects a venom that paralyzes the mussel, so it can pry the mussel open and eat the body. Humans eat them, and use their shells to make pearls and buttons.

They have a place in our cultural history. During the years between 1882 and 1914, beautiful pearls were taken from many of Tennessee's streams and "pearling" was a favorite sport for young people on Sunday afternoons at the turn of the century. After World War I, dams were built on many of the rivers, and the mussels lost their swift and shallow shoals. Also, the waters became more toxic and pearling became unprofitable.

A malacologist (one who studies mollusks), Neves has spent years and traveled the globe studying mussel conservation approaches. The three keys to mussel conservation are relocation, propagation and reintroduction, he says.

As part of his research, Neves has been reproducing species from the Clinch and Powell rivers in Virginia and Tennessee at Virginia Tech's recirculating aquaculture facility in a five-year project dealing with propagation and reintroduction. The Tennessee Wildlife Resources Agency and Virginia Tech have released more than 35,000 juveniles so far.

It will take five years to assess the success of the project, Neves says.