National Park Service

Appalachian Highlands Network (APHN)

Freshwater Mussel Monitoring

The Federally Endangered  Cumberlandian combshell (Epioblasma brevidens)
The Federally Endangered Cumberlandian combshell (Epioblasma brevidens)

Resource Brief: Freshwater Mussels Monitoring in APHN

There are currently no other documents or reports pertaining to this topic.

The monitoring protocol and procedures for this topic are currently under development.

For more information contact: Brian Witcher

Affected Parks

  • Big South Fork National River & Recreation Area (BISO)
  • Obed Wild & Scenic River (OBRI)

Importance / Issues

Both the Big South Fork NRRA and the Obed WSR protect nationally significant aquatic resources. The habitat protected by the Big South Fork is believed to be the best remaining freshwater mussel refugium in the Cumberland River system. In recent years, the Big South Fork has been the site for a mussel reintroduction effort aimed at restoring species which formerly occurred there, bringing the number of Federally Endangered species currently documented in the park to eleven. Along with many other significant aquatic resources, the Obed Wild and Scenic River protects one of four remaining populations of the Federally Endangered purple bean (Villosa perpurpurea), as well as a small number of Endangered Alabama lampmussels Lampsilis virescens), a species which was thought to have disappeared from the watershed until it was recently rediscovered upstream of the park.

Large declines in the mussel fauna since the turn of the twentieth century illustrate how rapidly changes can occur. Roughly 55 species were known from the Big South Fork at the turn of the century. Prior to the reintroduction effort currently underway, only 26 of these species remained in the river, 7 having gone extinct, vanishing completely from their historic range. Both parks are subject to a variety of potential upstream threats, including urban development, water withdrawal, agricultural activity and logging. In addition, the northern Cumberland Plateau, where BISO and OBRI are situated, produces more coal and oil than any other region in Tennessee, much of it coming from the parks' watersheds. Mining can cause contaminated mine drainage, sedimentation, and pollution from brine and other contaminants employed during mineral extraction operations. Because of the significance of the mussel fauna in these two river systems, the uncertainty of the outcome of reintroduction efforts, and the multitude of potential threats upstream from the parks, long-term trend data are needed to monitor changes in mussel populations.

Monitoring Objectives

Our specific objectives are to:

  1. Determine long-term trends in species composition and age class structure of freshwater mussel populations in the main stem rivers and major tributaries of BISO and OBRI.
  2. Determine long-term trends in the distribution and relative abundance of freshwater mussels at BISO and OBRI.
  3. Improve our understanding of the relationships between freshwater mussel communities and their habitats by correlating physical and chemical habitat measures with changes in mussel distribution, abundance and age class structure.

Preliminary Methods

Mussel surveys have been completed at both the Big South Fork and the Obed (Ahlstedt et al. 2001, Ahlstedt et al. 2002). Steve Ahlstedt (USGS, retired) and Monte McGregor (KDFWR) have contributed to the development of a long-term monitoring protocol which will incorporate the findings of these surveys, as well as the design of the mussel reintroduction project currently underway at BISO.

The final protocol will likely include a combination of timed searches as well as fixed transects for measuring population parameters. The number of individuals within different size classes will be an important metric, serving as a measure of recruitment and an indicator of population health. Timed searches for rare mussels will likely be undertaken because many of the listed mussels are so rare, and so widely scattered, that conventional transect methods are not adequate to detect trends.

In addition, a more comprehensive survey of the rivers and main tributaries will be periodically undertaken (every 5 to 10 years) to determine whether colonization is occurring in previously unoccupied sites.

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Last Updated: October 05, 2017 Contact Webmaster