|Scientific Name:||Noturus stanauli|
|Species Authority:||Etnier & Jenkins, 1980|
|Red List Category & Criteria:||Endangered B1ab(iii)+2ab(iii) ver 3.1|
|Reviewer/s:||Smith, K. & Darwall, W.R.T.|
|Facilitator/s:||Hammerson, G.A. & Ormes, M.|
This species is listed as Endangered because its extent of occurrence is less than 5,000 sq km, area of occupancy is less than 500 sq km, number of locations is two, and habitat is subject to ongoing declines in quality. Current population size and trend are unknown.
|Range Description:||The Pygmy Madtom occurs in the Tennessee River drainage, Tennessee (Page and Burr 1991, USFWS 1993). It has been found, and still exists, in only two short reaches of the Duck and Clinch rivers. These river reaches are about 600 river miles apart and separated by impoundments. No historical records exist for the reintroduction (nonessential experimental population; NEP) sites in the lower French Broad River or lower Holston Rivers, but historically the species was probably more widespread in the Tennessee River system and probably inhabited these waters (USFWS 2007).
The geographic boundaries of the NEP would extend from the base of Douglas Dam down the French Broad River, Knox and Sevier counties, Tennessee, to its confluence with the Holston River and then up the Holston River, Knox, Grainger, and Jefferson counties, Tennessee, to the base of Cherokee Dam and would include the lower eight kilometres of all tributaries that enter these river reaches (USFWS 2007).
|Range Map:||Click here to open the map viewer and explore range.|
Despite many thorough fish collections throughout the Tennessee River drainage, the species has been recorded from a total of only four discrete shoal localities in two rivers; distribution at these sites is very localized and densities are low.
Total adult population size is unknown but probably quite small (USFWS 2009). Observations or collections of this species are extremely difficult, and few records exist, despite numerous surveys at the two known sites and other nearby locations. At one annually surveyed site in the Clinch River, Pygmy Madtoms are only periodically collected; in the Duck River, a recent collection was the first in nearly 20 years (Shute and Biggins 1995). At the Clinch River site, which contains the best known population of pygmy madtoms, a total of 45 individuals were collected in (at least) annual fish surveys at this site between 1974 and 1996. However, individual catches have been extremely variable, and have ranged from one to 16 individuals; some surveys at this site yielded no Pygmy Madtoms (TVA Heritage Project data).
Probably this species has experienced a large decline, but the degree of decline is poorly known due to insufficient data.
Current trend is unknown. Since the species was listed as endangered in 1993, very few specimens have been found (USFWS 2009).
|Habitat and Ecology:||Habitat includes clear, moderate to large rivers, where the species has been collected on shallow pea-size gravel or fine sand shoals with moderate to strong current (USFWS 1993, 1994). Many occur in flowing portions of pools during the reproductive season (Dinkins and Shute 1993). Eggs are laid probably under slab rocks, in empty mussel shells, or in similar situations.|
Threats in the Clinch River include general deterioration of water quality from siltation and other pollutants associated with poor land use practices and waste discharges; potential threats include increased urbanization, coal mining, poorly managed agricultural practices, and impoundments (USFWS 1993, 1994). In Duck River historical collection sites, this species is seriously threatened by stream-bank erosion (USFWS 1993, 1994).
Habitat and water quality degradation remain the greatest threats to the madtom. The species remains highly vulnerable to extinction from stochastic events. None of the threats affecting the Pygmy Madtom have been eliminated since the fish was listed (USFWS 2009).
Actions needed (USFWS 1994):
|Citation:||NatureServe 2013. Noturus stanauli. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 13 December 2013.|
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