Race to Save the Golden Riffleshell

Photo Credit: Tim Lane, Virginia Department of Game and Inland Fisheries.

The quiet, pastoral landscape of remote southwestern Virginia was filled with sudden loud cheers when biologists managed to collect three golden riffleshell mussels (Epioblasma florentina aureola) from a stream near Cedar Bluff, Virginia. This endangered species – which is listed as the tan riffleshell (E. f. walkeri), despite a recent change in its scientific name – is now likely one of the rarest freshwater mussels on Earth. It survives only in a single, small and isolated population in Indian Creek, a tributary to the Clinch River, and biologists racing to save it from extinction were thrilled to discover that not only were the golden riffleshell they had found all female, they were also carrying glochidia, which is what immature, young mussels are called.



Photo Credit: Roberta Hylton, US Fish and Wildlife Service.





The golden riffleshell is just one of the many freshwater mussels species that call the Clinch River watershed home. In fact, the region boasts one of the most diverse assemblages of these freshwater animals in the U.S. With fanciful names such as birdwing pearlymussel (Lemiox rimosus), Appalachian monkeyface (Quadrula sparsa), and rough rabbitsfoot (Q. cylindrica strigillata), these animals provide a critical role, filtering and cleaning river water. They serve as “bio-indicators,” letting us know when something is not quite right in our waterways.

"We are lucky to have such incredible diversity right in our backyard and it is our responsibility to ensure its future," says Sarah Colletti of the Virginia Department of Game and Inland Fisheries. "If we can maintain healthy diverse freshwater mussel communities in our rivers, then we know we are doing a good job of protecting water quality too, and clean water is important to us all."

Over the years, the golden riffleshell and a number of other freshwater mussel species found in the Clinch River watershed have dwindled to precariously low numbers, and locating individuals has become highly problematic. Today, biologists believe there are less than a few hundred golden riffleshell left in a single stretch of stream.

Biologists with the U.S. Fish & Wildlife Service and Virginia Department of Game and Inland Fisheries have recognized for years now that the golden riffleshell and other freshwater mussels throughout the Upper Tennessee River Basin face incredible challenges to their survival. Though government regulations have brought about water quality improvements, freshwater mussels and fish are harmed wherever streams are affected by poor land use practices, mining, industrial spills, climate change, invasive species and other factors.



Photo Credit: Monte McGregor, Kentucky Department of Fish and Wildlife Resources





Biologists with the Service's Southwestern Virginia Field Office, Virginia Field Office, Kentucky Field Office, Virginia Department of Game and Inland Fisheries, Virginia Tech, Kentucky Department of Fish and Wildlife Resources, and The Nature Conservancy worked cooperatively and quickly this past March to extract the glochidia and return the females unharmed back to Indian Creek. The glochidia were transported to Kentucky's Center for Mollusk Conservation where scientists are using new techniques in an attempt to grow the species in captivity and help increase its population.

The golden riffleshell is on the brink of extinction. Still, conservationists hope that if we work hard and fast, we just may have a chance to save it.

While habitat conservation, restoration of water quality, and educating the public about the values of aquatic ecosystems are important components of recovery efforts, for the golden riffleshell, culturing (i.e., growing) this species in the laboratory is likely this species' last best hope. Culturing mussels isn't easy because the life cycle of a freshwater mussel is one of the most complex in the animal world.

In the past, biologists have used a variety of conventional techniques to propagate golden riffleshell, but success has been limited as numbers in the wild have continued to decline. However, efforts led by Monte McGregor of the Kentucky Department of Fish and Wildlife Resources Center for Mollusk Conservation to refine lab techniques for culturing mussels in serum extracted from the blood of rabbits offered new hope for saving the golden riffleshell. McGregor and his staff have been successful in propagating and culturing the tan riffleshell, which is closely related to the golden riffleshell, from the Cumberland River system in Kentucky. If the success using rabbit serum can be repeated for the golden riffleshell, biologists just might be able to accomplish their mission to save this small aquatic animal.



Photo Credit: Tim Lane, Virginia Department of Game and Inland Fisheries.





The determination of biologists who are partnering across state lines in Virginia and Kentucky is paying off. From the three gravid (with young mussels) female golden riffleshell collected in Virginia in March, the Kentucky Center for Mollusk Conservation has successfully used rabbit serum to rear about 12,000 glochidia to the juvenile stage. While there may be some mortality, this first batch of mussels appear to be among the healthiest ever cultured by McGregor and we expect a few thousand will make it to larger sizes suitable for reintroduction into the wild. Although some of the young mussels will remain at the Kentucky facility, by mid to late summer of this year, many will be transported to Virginia Department of Game and Inland Fisheries Aquatic Wildlife Conservation Center in Marion, Virginia, and Virginia Tech’s Freshwater Mollusk Conservation Center in Blacksburg, Virginia, to allow for continuous monitoring and growth. Eventually, if all goes well, the young golden riffleshells will be released back into the wild. The road ahead may be a long one, but the success of propagating golden riffleshell to date has provided new hope in the race to save this species.

Roberta Hylton, Supervisor of the Service's Southwestern Virginia Field Office, can be reached at roberta_hylton@fws.gov or 276-623-1233, ext. 22.

Leroy Koch, Fish and Wildlife Biologist in the Service’s Kentucky Field Office, can be reached at leroy_koch@fws.gov or 502-695-0468, ext. 106.

Jess Jones, Fish and Wildlife Biologist in the Service’s Virginia Field Office, can be reached at jess_jones@fws.gov or 540-231-2266.