PROFITS ON THE HALF SHELL: MUSSEL HARVEST MEANS BIG BUSINESS

Lying on the bottom of rivers and lakes, freshwater mussels quietly filter water. They don't do much else, but researchers and businessmen over the years have found the creatures fascinating.

Musseling or clamming, which is the harvest of mussels, is big business along the Mississippi River and rivers throughout the region.

The U.S. Fish and Wildlife Service reports a $50 million annual domestic business for shell companies in the United States and a $5 billion annual foreign trade to meet the demands for pearls, fine jewelry and other products.

"They are unique," said Jim Sickel, an expert on mussels at the Murray State University in Murray, Ky. "They sit there on the bottom of a lake or river and filter water for some 25 to 50 years. We think they play a major role in the ecology of the river or lake. They are just kind of neat animals."

Due to their larger size and greater thickness, shells of mussels from the South and Midwest have been in great demand for the last century.

From the 1890s until the 1950s, the Midwest was the center of the world button industry. Millions of shiny, white buttons were polished from freshwater mussel shells.

In the 1950s, though, plastics replaced shells in the manufacture of buttons.

"The Japanese discovered our mussel shells made the best cultured pearls," explained Sickel.

Most of the shells end up in Japan, where shell pieces are rounded into beads and implanted into live oysters. The bead is an irritant to the oyster and, in defense, the oyster secretes "nacre," a pearly substance, around the bead.

After two to three years, a cultured freshwater pearl is formed. The larger the original bead, the larger the resultant pearl.

"The shell material from North America is the best from anywhere in the world," Sickel said.

However, about two years ago, the Japanese pearl industry went into a slump. For an unexplained reason, many oyster beds died, Sickel explained, and the demand for mussel shells shrunk. But as the beds are redeveloped, the demand is on the rise.

While found on every continent except Antarctica, freshwater mussels are most diverse in the Mississippi and Ohio river drainages.

In the United States, the industry is primarily based along the Mississippi River drainage area, with the largest companies predominantly in Tennessee.

Of some 300 known species of mussels, 30 are extinct and another 70 are listed as threatened or endangered. At least 45 percent are considered in danger or decline.

Among those species are those mussels valuable in commercial trade, explained Alan Buchanan, environmental services biologist with the Missouri Department of Conservation.

"The industry at times has been quite large," Buchanan said.

In the early 1980s, the average price of some mussel species went from about 30 to 50 cents a pound to more than $7 a pound.

A good day could yield a ton of shells for a mussel diver.

"There was a lot of money to be made," he said.

As a result, many of the biggest mussel beds were fished out, and biologists began to worry about the survival of those species of mussels.

Organizations were formed to try to regulate and track commercial musseling. And two major arrests of illegal harvest brought attention to the severity of the problem.

The most recent arrest was in January and involved an Iowa exporter.

A.J. Hendershott at the Missouri Department of Conservation's Cape Girardeau office, said mussels can be found throughout the area.

"You can go out and look on the banks of the Mississippi River and find mussel shells on the shore," he said.

Mussels can be found in Apple Creek, the Whitewater River and the Black River. Many are found in Bootheel ditches.

"But without the proper habitat, they can't survive," Hendershott said.

The Missouri Department of Conservation has set a daily limit of five for freshwater mussels.

A commercial fishing license is required for those interested in harvesting and selling mussels.

Missouri's interior waterways are closed to mussel harvest with the exception of the Missouri River and a portion of the St. Francis River in the Bootheel along the Missouri and Arkansas border.

Commercial musseling in Mississippi River channels and ditches in Southeast Missouri is prohibited. Sport fishermen may take just five mussels daily.

Even the mussels that aren't harvested for commercial use are on the decline, indicating a change in the nation's freshwater sources.

"We attribute part of the decline to over harvest, but more is due to pollution and habitat changes," Buchanan said.

Mussels are sensitive to changes in the water. For example, a particular mussel that likes swift flowing streams has been declining as dams and channels are built.

"We know the system is changing," Buchanan said. "Often we refer to mussels as `canaries in a coal mine.' If these are the canaries dying out, what's next?"