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Freshwater mussels

Out of 511 species assessed globally, 44% of freshwater mussels listed on the IUCN Red List are classified at some level of threatened.

There are 297 known freshwater mussel taxa in the United States and Canada, which are home to the most diverse freshwater mussel fauna in the world, especially in the southeastern United States. Of the 297 known species, 213 (71.7%) taxa are listed as endangered, threatened, or of special concern. Approximately 37 North American species were considered extinct in 2004.

Out of 16 recognized freshwater mussel species in Europe, 12 are considered threatened, with varying statuses from Near Threatened to Critically Endangered. 8 species are protected by the European Union Habitats Directive across all annexes.

There are approximately 85 known species in Africa, 102 in Central America, 74 in South America, 228 in Asia (with the highest species diversity in Southeast Asia), and 33 in Australasia. The species in these areas are not as well researched as in North America and Europe. Approximately 61% of freshwater mussels in Asia had not been assessed and conservation efforts were almost non-existent. No Asian mussels were protected internationally under legislation such as CITES.

The main factors contributing to the decline of freshwater mussels include destruction by dams, increased siltation, channel alteration and the introduction of invasive species such as the zebra mussel.