News Release

Endangered Freshwater Species Shows Signs of Population Increases

(L) Adult female tan riffleshell. (R) Baby tan riffleshells.

NPS Photo

News Release Date: November 18, 2025

Contact: Tom Blount, 423-569-9778

Oneida, Tennessee: An endangered freshwater mussel species in the Big South Fork National River & Recreation Area is showing signs of natural population increases for the first time. The tan riffleshell (Epioblasma walkeri) is an endangered mussel found in only a few locations within the Big South Fork of the Cumberland and the upper Clinch Rivers. The National Park Service has been collaborating with the Kentucky Department of Fish & Wildlife Resources to monitor the status of this rare species.

Recently, staff from both agencies have been working together to recover the Big South Fork populations of this species by supplementing their numbers. Male and female tan riffleshell mussels were collected from Big South Fork and used to produce thousands of baby mussels. These small mussels have been added to limited locations where the species is known to exist at Big South Fork over the last few years.

A recent mussel survey at the Big South Fork found the tan riffleshell at sites not previously known to have the species. Most exciting about this discovery was that some of the riffleshells found were juveniles, which suggests that the Big South Fork population is growing and spreading naturally due to the recovery efforts.

“We are delighted that water quality in the Big South Fork is now able to support this species. Because mussels are filter feeders, they are highly sensitive to pollution, and their presence can offer a reliable assessment of the river they inhabit,” said Superintendent Niki Stephanie Nicholas.

For more information, please contact Big South Fork NRRA at 423-569-9778.

 

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