Pheasantshell

Habitat

The Pheasantshell inhabits shallow, fast-flowing riffles of small streams to large rivers. It prefers a stable substrate composition of mixed sand and gravel.

Distribution

The Pheasantshell occurs throughout the upper Tennessee River basin in southwest Virginia.

Life History

Freshwater mussels have a very unique life cycle. Parasitic larvae, called glochidia, develop in the gills of the female mussel. Once mature, the glochidia are expelled from the gills of the mussel and must attach to the gills of a suitable host fish, where they complete their transformation into a juvenile mussel. They then detach from the fish and begin their free-living existence on the river bottom.

Some freshwater mussels are host-specialists, meaning that metamorphosis can only occur on a limited number of closely related fish species, while others are host-generalists, with the ability to complete their life cycle using many different species. The Pheasantshell has a variety of suitable hosts including Banded Sculpin (Cottus carolinae), Black Bass (Micropterus spp.), Sauger (Sander canadensis), Walleye (Sander vitreus vitreus).

Conservation

The Pheasantshell has experienced dramatic population declines in the Tennessee portion of the Clinch River since 2016, when a mass die-off of freshwater mussels was first reported. The Pheasantshell is disproportionately affected during these die-offs, which occur annually, with up to 90% population loss estimated at shoals in Tennessee. However, Pheasantshell populations in Virginia remain large, as only the lowermost reach of the Clinch River is affected in the state.

Research into the cause of these die-offs and the pathology of freshwater mussels is ongoing, and both DWR’s Aquatic Wildlife Conservation Center (AWCC) and Virginia Tech’s Freshwater Mollusk Conservation Center (FMCC) continue to propagate and augment populations throughout its range. Additionally, long-term monitoring efforts carried out by DWR staff and partners throughout the upper Tennessee River basin helps to inform these conservation efforts by tracking population dynamics over time.