Peril and Promise for America’s Vital Endangered Freshwater Mussels

mussel group

Mussels including mucket (Ortmanniana ligamentina) and plain pocketbook (Lampsilis cardium) in the Kankakee River near Kankakee, Illinois, during a freshwater mussel survey GZA GeoEnvironmental Inc. conducted in 2021. Photo credit: Michael Jochheim/GZA

by | May 8, 2024

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With names like pimpleback, Wabash pigtoe, fatmucket, and pink heelsplitter, freshwater mussels may be among our country’s least glamorous and least appreciated wildlife species. But few creatures matter more to our freshwater ecosystems and our environment as a whole–or are as profoundly endangered, either.

Over the last century, more than 25 species of freshwater mussel have gone extinct in the United States, largely because of pollution, dam construction, and other habitat disturbances. Today, another 89 species are listed by the U.S. Fish and Wildlife Service as threatened or endangered, including dozens that call the Mississippi and Ohio Rivers and their tributaries home.

Although the outlook for freshwater mussels appears dire, as someone who works regularly to protect them–and recently helped plant my 10,000th freshwater mussel in one of dozens of relocation projects I’ve worked on–I’m feeling more optimistic than I’ve ever been in my career about their prospects. It’s a guarded and tentative optimism, to be sure, but I’m encouraged by several positive signs.

Maybe the single best trend is the widespread, growing awareness of just how critically important freshwater mussels are to human, animal, and overall environmental health. From Illinois to Virginia to Michigan to Alabama, we see more and more public officials, environmental activists, and wildlife advocates speaking out about the importance of saving these animals often called “the liver of the river.”

Each freshwater mussel living in a river or stream not only can filter and clean anywhere from 10 to 20 gallons of water per day, they’re also being appreciated as never before as an early-warning system for overall waterbody health. If freshwater mussels are dying out in a stretch of stream or river, that’s now widely understood as a flashing indicator of pollution, poor water flow, or other stressors on a river or stream that need to be addressed to protect the fish, reptiles, plants, birds, and mammals that depend on them. It’s not just flora and fauna that are in danger when freshwater mussels suffer, but the safety and availability of fishing, recreational properties, and public water supplies as well.

Greater recognition is driving funding and action for freshwater mussels. In Virginia, officials are now working to secure $400,000 in funding for biologists to develop statewide plans to protect and restore native freshwater mussel species. Another $300,000 from a pollution-remediation settlement in the city of Alexandria is being used to help Virginia’s Department of Wildlife Resources cultivate freshwater mussel populations in the Potomac and James Rivers.

This year the Western Pennsylvania Conservancy is expected to begin working to restore freshwater mussels to part of the West Branch of the Susquehanna River after winning funding from the Chesapeake Watershed Investment for Landscape Defense (ChesWILD).

Now underway across 13 states is a comprehensive, three-year study of freshwater mussel conditions being led by the U.S. Forest Service and advocacy group American Rivers with support from the Band Foundation, Merck Family Fund, and Tennessee Valley Authority.

Facilities in several states are bolstering capacity to spawn freshwater mussels by the tens of thousands to seed long-term, naturally reproducing populations in habitats where they’re especially needed and valuable. At the Columbus Zoo and Aquarium in Ohio, Watters Aquatic Conservation Center scientists have even succeeded in perfecting the use of in-vitro fertilization to accelerate the breeding of freshwater mussel populations.

Researchers from the National Museum of Natural History, Field Museum of Natural History, and Virginia Polytechnic Institute recently launched a smartphone app called MusselMapR that collects more than 410,000 records of 302 different species of mussel specimens from 45 natural history collections. MusselMapR centralizes a trove of smartphone-searchable information about where species are faring best and habitats they appear to prefer, including river size, slope, and speed of flow.

The U.S. Fish and Wildlife Service has announced plans to protect several additional species of freshwater mussels by adding them to the federal list, including the salamander mussel, Cumberland moccasinshell, Tennessee clubshell, and Tennessee pigtoe. Many other species of mussels are receiving state-level protections: For example, in West Virginia, the sheepnose, snuffbox, and spectaclecase were recently added to the state priority list for expedited recovery planning.

It’s saddening–and sobering–that so many species of vitally important freshwater mussels continue to face existential threats. But across a growing swath of the United States, moves to mobilize laws and regulations to protect freshwater mussels epitomize the growing recognition of mussels’ value as both harbingers of and contributors to river health–and to ensure that pimplebacks, pigtoes, fatmuckets, and all of their cousins survive and flourish for centuries to come, for everyone’s benefit.

About the Author: In her 10 years of working with freshwater mussels at GZA and predecessor workplaces, Elisabeth Hollinden has led or participated in 74 mussel surveys and/or relocations and has observed more than 10,600 individual mussels. She holds federal permits to perform mussel recovery projects in Illinois and 16 other states across the Midwest, Mid-Atlantic, and South.

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