Freshwater Mussel Relocation Project: Endangered Species of Mammoth Cave

A park scientist examines several of the recently collected freshwater mussels.

NPS Photo

The Green River in Mammoth Cave National Park contains some of the most diverse populations of freshwater mussels in North America. Over 50 species of mussels are found within the park with several species included on the federally endangered list.

A park scientist identifies different freshwater mussel species including Pigtoe, Pocketbook and Pistol Grip mussels.

NPS Photo

Mussels are indicator species. They may live up to 100 years, are typically stationary, and highly sensitive to environmental changes. From them, we can learn a great deal about long term river and stream health. Just like we can look at tree rings and study the changes in climate, rainfall, forest conditions through the years, mussel biologists can look at the rings etched into mussel shells to understand changing stream conditions. Negative impacts that threaten these incredible mussels and their habitats include:

• Dams

• Eutrophication

• Runoff from fertilizer and animal wastes

• Chemical runoff

• Nonnative species

• Sedimentation from erosion and dredging

A diver on the May 2019 freshwater mussel relocation team searches the Green River Ferry Crossing for mussels near the Green River Ferry.

NPS Photo

In May 2019, before construction on the north Green River Ferry ramp, Mammoth Cave National Park relocated about 2,500 mussels so they would not be impacted by construction, dredging, and damming. In September 2020, the National Park Service worked with the Kentucky Department of Fish and Wildlife Resources to stock about 2,400 endangered mussels into the Green River in the park. During these events, trained divers collected 28 species of mussels including two species of federally endangered mussels: fanshell (Cyprogenia setgaria) and sheepnose (Plethobasus cyphyus). This effort also aims to reintroduce and restore the federally endangered rayed bean mussel (Villosa fabalis), which has not been found in Kentucky in over forty years. A population of rayed bean mussels were moved from the Allegheny River in Pennsylvania due to a tar spill, hundreds of these mussels were released into waterways across Kentucky, including sections of the Green River contained in the park. If successful the initiative will bring back the rayed bean to its historic Kentucky range.

Collection of freshwater mussels or mussel shells is strictly prohibited in Mammoth Cave National Park. The Green River in the park is home to a number of federally endangered mussel species and protection of mussels in the park is strictly enforced. Do not disturb mussels for any purpose.