Noturus stanauli Pygmy Madtom

 

The federally endangered Pygmy Madtom is only known from the Duck River, Humphreys and Hickman counties, Tennessee and the Clinch River, Hancock County, Tennessee. These rivers are separated by 600 miles and there are no other historic records for the species within the Tennessee River drainage. 

 

In 2000, two Pygmy Madtoms were found at Frost Ford and given to CFI for captive propagation. These madtoms spawned successfully at CFI and produced 2 nests with 10 and 19 eggs respectively. Thirteen madtoms survived to adult size as a result of this propagation effort. CFI noted that the adult madtoms were only active in the early evening hours, leading CFI to believe that Pygmy Madtoms are crepuscular. In 2002, six madtoms were released back into the Clinch River at Frost Ford. Two wild caught individuals were taken back to CFI for propagation efforts. The 2002 captive propagation effort only produced 1 juvenile Pygmy Madtom. In 2004 and 2005 no madtoms were found during surveys for propagation efforts, although CFI conducted surveys at 5 sites in the Clinch River.

 

In May 2007, CFI found 3 female and 2 male Pygmy Madtoms in the Clinch River. Again, CFI brought this fish to the facility to attempt captive propagation and produced 7 juvenile madtoms from the propagation effort that spawned in their facility in 2008. They noted that the madtom appears to be relatively stable, albeit very rare in the Clinch River. 

Threats affecting the Pygmy Madtom are increased urbanization, coal mining, toxic chemical spills, siltation, improper pesticide use, and streambank erosion remain threats to the pygmy madtom.  Additional threats to the madtom include gravel dredging, water withdrawals, and agricultural practices. None of the threats have been eliminated since the fish was listed; consequently, both the Duck and Clinch River populations remain vulnerable to extirpation.  Existing Federal and State laws and regulations are applied to actions conducted within the range of Pygmy Madtom to protect the fish and its habitats.  However, due to difficulty in finding the fish in surveys the extent of its habitat is unknown.

 

The Pygmy Madtom is known from only two disjunct populations in the Tennessee River system.  Since the species was listed as endangered in 1993, fewer than 10 specimens have been found from both the Duck and Clinch River populations.  Habitat and water quality degradation remain the greatest threats to the madtom.  Captive propagation for the Pygmy Madtom has shown limited success due to difficulty in finding individuals for broodstock.  Therefore, the species remains highly vulnerable to extinction from stochastic events.