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Questions and Answers

Sheepnose and Spectaclecase Mussels Listed as Endangered

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Sheepnose mussels by USFWS; Kristen Lundh

The sheepnose is a freshwater mussel found in the Mississippi River watershed.

Photo by USFWS; Kristen Lundh


What action is the Service taking?

The Service is listing two freshwater mussels, the sheepnose and spectaclecase, as endangered, under authority of the Endangered Species Act.  To list these mussels as endangered, the Service first published a proposed rule in the Federal Register on January 19, 2011 that opened a 60-day public comment period.  The Service then gathered and analyzed the public comments and new information received.  Based on this analysis, the Service determined that these mussels are in danger of becoming extinct and therefore, the Service is now publishing a final rule in the Federal Register that adds the sheepnose and spectaclecase to the list of endangered species.


Why is the Service listing the sheepnose and spectaclecase mussels as endangered?

The sheepnose has declined significantly across its original range. Once found in 76 rivers and streams, today it is found in only 25, a 67 percent decline in occupied rivers.  Large-river habitat throughout nearly all of the sheepnose mussel’s range has been impounded, leaving short, isolated patches of riverine habitat in areas between dams.  Virtually all sheepnose populations are at risk of extinction because threats are exacerbated as a result of the small size and isolation of remaining populations.


The spectaclecase, too, has declined significantly across its range.  Historically, the spectaclecase was known from 44 streams in 14 states and is now found in 20 streams in 11 states, a 55 percent decline.  Like the sheepnose, all remaining populations face threats that are exacerbated by the small size and isolation of those populations.


The remaining populations of sheepnose and spectaclecase mussels are threatened by impoundments, point and nonpoint source pollution, sedimentation and physical changes in streambed structure.


Where are the sheepnose and spectaclecase mussels found?

The sheepnose is found in Alabama, Illinois, Indiana, Iowa, Kentucky, Minnesota, Mississippi, Missouri, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Wisconsin.

The spectaclecase is found in Alabama, Arkansas, Illinois, Iowa, Kentucky, Minnesota, Missouri, Tennessee, Virginia, West Virginia, and Wisconsin. It has been extirpated from Indiana, Kansas and Ohio.


Why should we be concerned about the potential extinction of freshwater mussels?

North America has the highest diversity of freshwater mussels in the world.  Of the 300 freshwater mussel species in North America, 38 have gone extinct during recent history and another 77 species are considered critically imperiled.  Mussels, because they can close their shells for protection and tend to be long-lived, respond to long-term ecological changes rather than short-term disturbances.  Loss and imperilment of so many species indicate long-term harmful trends in our waterways that affect many aquatic species as well as people who depend on those waterways for drinking water and recreation.


Additionally, mussels are important members of their ecosystems.  Mussel beds provide habitat for aquatic invertebrates and fish; raccoons, otters, and wading birds eat mussels; and mussels filter water, benefiting water quality.


How will listing as endangered help conserve these mussels?

Listing under the Endangered Species Act can help save the sheepnose and spectaclecase mussels by raising awareness of their presence, focusing conservation planning and funding, and providing additional opportunities and partners.  Also, Endangered Species Act regulations protect these mussels from intentional and unintentional harm. 


The Endangered Species Act requires that recovery plans be prepared for the sheepnose and spectaclecase.  Recovery plans will identify and prioritize actions needed to conserve and recover these mussels so that they are no longer at risk of extinction.  Non-government agencies, universities, tribes, and other federal and state agencies often carry out conservation actions identified in recovery plans. 


Federally listed threatened and endangered plants and animals are usually considered as priorities during land use planning.


The Endangered Species Act prohibits all federal agencies from jeopardizing the existence of listed plants and animals.  As a result, adverse impacts to listed species from federal actions are avoided, minimized, and mitigated.


Freshwater mussels are harvested commercially for use in the Japanese pearl cultivation industry.  Endangered Species Act protection prohibits the take of endangered or threatened species, helping to ensure that harvesting does not cause the extinction of a mussel species.


How can I get more information?

Information about sheepnose and spectaclecase mussels and their listing is available on our website at http://www.fws.gov/midwest/endangered.


For more information about the sheepnose mussel, you may also write or phone:


Richard Nelson, Field Supervisor
U.S. Fish and Wildlife Service
Rock Island, Illinois Ecological Services Field Office
1511 47th Ave.
Moline, Illinois 61265

Telephone 309-757-5800


For more information about the spectaclecase mussel, you may write or phone:


Tony Sullins
U.S. Fish and Wildlife Service
4101 American Boulevard East
Bloomington, MN 55425

Telephone: 612-725-3548



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