Freshwater Mussels and Pearls
Posted On: 07/26/2017 - 4:48pm, Posted By: Emily Imhoff, Collections Manager - Zoology
This post is guest-authored by Stanley Hedeen, professor emeritus at Xavier University and long-time volunteer at the Geier Collections & Research Center.
The zoology collection at the Cincinnati Museum Center holds several thousand mussel shells taken from the Ohio River, Mill Creek, Licking River, and other regional streams. About 70 species of mussels are native to the Cincinnati and Northern Kentucky area. The body of a mussel is encased between its two shells, or valves, arranged right and left. Adductor muscles hold the shells together by counteracting a ligament that pushes the shells apart. Mussels obtain their food by filtering microorganisms and detritus from the water passing over their gills. Many species are threatened, endangered, or even extinct due to habitat alteration from construction and operation of dams, and historical pollution of waterways.
Prior to the settlement of the region in the late eighteenth century, Native Americans ate mussels and fashioned the shells into spoons, bowls, and hoes. Ornamental beads and disks were cut from shiny shell linings and drilled for stringing. Shells also were charred and crushed to be used as tempering grit in the making of clay pottery. Finally, pearls found in the mussel shells were collected and included in human graves. Archaeologists recovered approximately 36,000 pearls weighing 23 pounds from a single Native American burial mound near Newtown, Ohio.
A Fort Ancient (ca. AD 1000 to AD 1650) hoe was made by inserting a stick into a hole drilled through a mussel shell.
The settlers that displaced the Native Americans rarely gathered mussels for food. However, as freshwater pearls increased in value during the mid-nineteenth century, area residents resumed collecting mussels to search for the gems. Pearl hunters working in local rivers sold their finds to buyers such as the Little Miami Pearl Fisheries of Waynesville, Ohio. The Waynesville firm in 1888 provided Tiffany & Company with about 2,000 green, pink, white, and purplish-brown pearls, an assemblage that won a gold medal at the 1889 Paris Exposition as the world’s finest collection of freshwater gems. Nevertheless, the regional pearl business ceased at the beginning of the twentieth century, largely because jewelry customers grew to prefer spherical, button-shaped, or pear-shaped cultured marine pearls while natural freshwater pearls are almost always irregular in shape.
An irregularly-shaped natural freshwater pearl and a spherical marine pearl.
Today, mussels are still harvested legally and illegally for the pearl industry – but not for the pearls they produce themselves. Freshwater mussel shells are cut into pieces which are then shaped into small spheres. These are placed into saltwater-dwelling pearl oysters, which cover the shell sphere with layers of shiny nacre. Most cultured saltwater pearls are made in this way. Harvesting freshwater mussels, many of which are threatened or endangered, is illegal in many states. Several people have been arrested, fined, and jailed for illegally harvesting endangered mussel species in Ohio and other nearby states in recent years.