Freshwater Mussels

washboard musselFreshwater mussels are also called shellfish, clams, bivalves, and unionids.  Mussels are important to both man and the environment.  Because they are filter feeders, mussels serve as natural water filters and act as indicators of water quality conditions.  Freshwater mussels also serve as food for many types of animals.  Alabama has one of the richest and most diverse assemblages of mussels in the world with 180 species.  Approximately two-thirds of North American mussel species have been reported from Alabama.

With the high numbers and variety of shells in the Southeast, it is not surprising that some mussels have substantial commercial value.  In the early 1900s mussel shell was the primary raw material for the button industry, and the industry harvested thousands of pounds each year.  The development of plastics in the 1940s reduced the demand for mussels as a button source, and populations began to recover from intense unregulated harvest. 

Today, mussel shell is exported for use in the production of cultured pearls.  Sections from a mussel shell are cut out, partitioned, rounded, polished, and inserted into oysters as the pearl nuclei.  After a period of time, the cultured pearl is removed from the oyster and used in jewelry production. 

The Tennessee River is currently the most important source of commercial mussels in the world.  The Alabama River system also contributes considerably to the U.S. shell export.  The yearly value of exported shell has been more than $20 million.

Although mussel populations can withstand regulated harvest, other factors have led to a decline in mussel numbers and species.  Factors such as the impoundment of rivers, channelization, pollution, modern industrialization and urban development, erosion, and siltation have significantly affected mussel populations.  Almost one half of Alabama’s mussels are considered extinct, extirpatedthreatened, endangered, troubled, or of special concern.  Proper management, protection and monitoring of the surviving native mussel resources (especially habitat) are essential to preserve this biologically diverse group.

Commercial Musseling Regulations

The State of Alabama sets certain guidelines on the harvest of freshwater mussels.  Consult the current regulations for species, size restrictions, and other harvest information.  If you collect a non-commercial mussel, return it immediately to the river.  If you believe it to be endangered, threatened, or rare, take a photo of it, if possible, before returning it to the water; and contact a Fisheries Section office.  By reporting these findings, you will help mussel biologists studying these uncommon mussels.  Possession of any part of a protected species is illegal, and penalties for a violation may include a fine and imprisonment.

A PDF of an Outdoor Alabama magazine article on Alabama's mussels, Diversity of Freshwater Mussels in Bear Creek.

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