Wisconsin's Threatened &
Endangered Mussels

Freshwater mussels (also referred to as clams, naiads, or unionids) reach their greatest diversity in North America where some 300 species occur. However, surveys conducted over the past several decades have documented significant declines in freshwater mussel populations. Many populations have been locally extirpated and others are failing to reproduce. Primary factors responsible include extensive habitat modification and destruction, commercial exploitation, water contamination, and competition with exotic species. Malacologists (mollusk specialists) estimate that nearly half of these species are presently threatened, endangered, or extinct and that freshwater mussels are considered to be the most endangered group of animals in North America.

Recovery of these and other imperiled aquatic species will require long-term efforts to improve the water quality of our lakes and rivers and to restore riverine and riparian systems to more natural conditions. In addition, greater knowledge of the biology and ecology of freshwater mussels will be needed if we are to prevent their extinction and encourage their reproduction. In Wisconsin, 19 of our 51 species are listed as threatened (THR) or endangered (END).

Species information from the book The Endangered and Threatened Invertebrates of Wisconsin:

The content for this page was originally presented in the Endangered and Threatened Invertebrates of Wisconsin, a free publication available by contacting the Endangered Resources Program.