Center for Biological Diversity

For Immediate Release, July 25, 2023


Tierra Curry, (928) 522-3681,

Freshwater Mussel Proposed for Protection in Seven Eastern States

Protecting Green Floater Will Improve Water Quality

WASHINGTON— In response to a legal petition from the Center for Biological Diversity, the U.S. Fish and Wildlife Service today proposed to protect the green floater, a freshwater mussel found from New York to North Carolina, as threatened under the Endangered Species Act. The Service also proposed designating 1,586 stream miles of critical habitat.

“Protecting the green floater under the Endangered Species Act will save this mollusk from extinction and also benefit people who rely on rivers for clean drinking water and recreation,” said Tierra Curry, a senior scientist at the Center. “Taking steps to save freshwater mussels is good for river wildlife and good for people.”

Green floaters have been lost from nearly half their historical range and are now found in Maryland, New York, North Carolina, Pennsylvania, Tennessee, Virginia and West Virginia. They are no longer found in Alabama, Georgia, New Jersey or Washington, D.C.

The green floater was first identified as a candidate for federal protection in 1991. The Center and its allies filed a petition seeking protection for the mussels in 2010.

Critical habitat designation requires that any federally funded or permitted project in the area must take steps to avoid degrading the mussel’s habitat. The streams proposed for protection as critical habitat for the green floater are found in the Potomac watershed in Maryland, Pennsylvania and West Virginia; the Susquehanna watershed in New York and Pennsylvania; the Kanawha watershed in North Carolina, Virginia and West Virginia; the Chesapeake and Chowan-Roanoke watersheds in Virginia; and the upper Tennessee, Neuse-Pamlico and Chowan-Roanoke watersheds in North Carolina.

Green floaters are smaller than 3 inches and have thin, trapezoid-shaped, green-striped shells that are tannish yellow to green on the outside and silvery salmon on the inside. They only live three to four years which makes them highly vulnerable to severe events like ongoing droughts or lingering pollutants that could wipe out an entire generation.

Like most bottom-dwelling river species they are threatened by silt that enters the water from agricultural fields, logging, mining and construction. Freshwater mussels are also highly sensitive to pollution including oil and gas byproducts, pesticides, livestock wastes, road run-off and sewage treatment plant effluent. Mussels are also sensitive to water temperature and populations are declining as rivers heat up.

Green floaters are unique among mussels because they can incubate their own larvae and do not require a host fish to reproduce, though a variety of fish species can host the juvenile mussels on their gills to carry them upstream.

“There’s no shortage of bad news about declining wildlife populations, but the animals that get federal protection and funding are the ones that are increasing,” said Curry. “With funding we can reverse wildlife population declines, we just have to make saving biodiversity a top priority.”

Freshwater mollusks are the most endangered group of animals in North America with more than 70 aquatic snails and 36 freshwater mussels already having been lost to extinction. Nearly 70% of U.S. freshwater mussels are at risk of extinction, but only 30% are protected under the Endangered Species Act.

The Endangered Species Act, which turns 50 this year, has saved 99% of the plants and animals under its care, and 90% of the 1,800 listed species are moving toward recovery.

RSGreen floater mussel - Ryan Hagerty - USFWS
A green floater mussel, Lasmigona subviridis. Photo by Ryan Hagerty/USFWS. Image is available for media use.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.7 million members and online activists dedicated to the protection of endangered species and wild places.

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