Freshwater Mussel Conservation
 Freshwater mussels are found worldwide, but reach their greatest diversity in eastern North America where they number around 300 species. Over 90% of these are found east of the Rocky Mountains. Recent stream surveys throughout North America and other parts of the world have documented drastic declines in mussel populations, and mussels may be the most endangered group of animals for which we have good data. According to Williams et al. (1993), of the 300 species of mussels which were once present in the United States and Canada about 70% are either extinct (21 species), endangered (77 species), threatened (43 species) or of special concern (72 species). The Fish and Wildlife Service maintains a website listing many of these threatened and endangered species.
Some genera have been particularly hard hit. For example the genus Epioblasma historically had around 25 species and subspecies. Today 14 of those are likely extinct, 10 are endangered and near extinction and the remaining species is listed as endangered in most states throughout its range.
Factors responsible for the decline of freshwater mussels include siltation, chemical pollution, loss of habitat through the creation of impoundments, channelization or other stream modifications and impacts form exotic species like the zebra mussel. The effects of these mussel hazards have been discussed in more detail in a web article by Williams & Neves.
Members of the Unionoida have been directly exploited by humans for millennia. Freshwater mussels were used by Native Americans as food, source material for tools, and ornamental objects. Their importance to Native Americans is revealed by the large shell mounds associated with village located along streams with abundant mussel populations.
 Freshwater mussels are also important commercially in modern society. Beginning around the 1890s, mussels were harvested and used in the manufacture or buttons for clothing. Many of the towns along the larger streams of North America like the Mississippi, St. Croix and Illinois rivers had button factories or buying stations where musselors sold their shells. The Illinois State Museum provides an interesting resource called "Harvesting the River" that provides more information about the freshwater pearl button industry.
The decimation of freshwater mussel populations through both habitat destruction and over-harvesting has mobilized conservation-minded folk to try and reverse this trend. Many of these people from academia, business and government agencies have joined forces to form the Freshwater Mollusk Conservation Society.
However, it is because of the decline of freshwater mussels in North America and their commercial value that we know as much as we do about unionoid biology. The desire in the early part of the 20th century to propagate mussels uncovered a truly fascinating life history, and we have still only scratched the surface!
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