|Scientific Name:||Etheostoma susanae|
|Species Authority:||(Jordan & Swain, 1883)|
Boleosoma susanae Jordan & Swain, 1883
|Red List Category & Criteria:||Endangered B1ab(iii)+2ab(iii) ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
This species is listed as Endangered because extent of occurrence is less than 5000 sq km, area of occupancy probably is less than 20 sq km, distribution is severely fragmented, and habitat quality is declining. Population size and trend are unknown.
|Range Description:||This darter occurs in the Cumberland River drainage above Cumberland Falls in eastern Kentucky (Strange 1998) and adjacent Tennessee (USFWS 2011). Recent surveys by O'Bara (1988) and Laudermilk and Cicerello (1998) indicate that the Cumberland Darter is restricted to short reaches of 16 small streams in the upper Cumberland system in Whitley and McCreary counties, Kentucky, and only two small streams in Tennessee (one in Scott County and one in Campbell County). The species has apparently been extirpated from Little Wolf Creek, Whitley County, Kentucky, where it was recorded by Jordon and Swain (1883), and Gum Fork, Scott County, Tennessee, where it was recorded by Shoup and Peyton (1940). Also, although O'Bara (1988) recorded the Cumberland Darter from two sites in the mainstem of the Cumberland River, recent efforts to recollect the species from these sites have been unsuccessful (Ron Cicerello, Kentucky Nature Preserves Commission, Frankfort, Kentucky, personal communication, 1999). Previous records of the species in the Poor Fork portion of the Cumberland River drainage in Letcher and Harlan counties, Kentucky (Starnes and Starnes 1979), have been determined to be the Johnny Darter (Etheostoma nigrum) based on a genetics study conducted Strange (1998). Records of the species from Martins Fork, Harlan County, Kentucky (Starnes and Starnes 1979), are also believed to misidentifications; however, efforts to collect individuals from Martins Forks for genetic studies have been unsuccessful, indicating that whichever taxon occurred in this system has apparently been extirpated. [Primary source: USFWS 2001]|
|Range Map:||Click here to open the map viewer and explore range.|
Currently, the species is known from 15 localities in a total of 13 streams in Kentucky (McCreary and Whitley counties) and Tennessee (Campbell and Scott counties). All 15 extant occurrences are restricted to short stream reaches, with the majority believed to be restricted to less than 1.6 kilometres of stream. These occurrences are thought to form six population clusters (Bunches Creek, Indian Creek, Marsh Creek, Jellico Creek, Clear Fork, and Youngs Creek), which are geographically separated from one another by an average distance of 30.5 stream kilometres. Source: USFWS (2011, which see for various primary sources).
No population estimates or status trends are available for the Cumberland Darter; survey results suggest that the species is uncommon or occurs in low densities across its range (see USFWS 2011).
Though recorded as abundant by Jordan and Swain (1883), this fish is now considered to be rare and extremely restricted in range.
Based on collection efforts reported through 2007, the species appears to be extirpated from 11 historical collection sites and a total of 9 streams. Source: USFWS (2011, which see for various primary sources).
Current population trend is unknown but probably relatively stable or declining to some degree. Habitat quality probably is declining.
|Habitat and Ecology:||This fish inhabits shallow water in low velocity shoals and backwater areas of moderate to low gradient stream reaches with stable sand or sandy-gravel substrata. It is not found in areas with cobble or boulder substrata. All specimens that have been collected in recent years have been found in less than 15 centimetres of water (O'Bara 1988, Laudermilk and Cicerello 1998).|
USFWS (2011) summarized threats as follows:
Habitat loss and modification represent significant threats to the Cumberland darter. Severe degradation from sedimentation, physical habitat disturbance, and contaminants threatens the habitat and water quality on which the Cumberland Darter depends. Sedimentation from coal mining, logging, agriculture, and development sites within the upper Cumberland basin negatively affect the Cumberland Darter by reducing growth rates, disease tolerance, and gill function; reducing spawning habitat, reproductive success, and egg, larvae, and juvenile development; modifying migration patterns; reducing food availability through reductions in prey; and reducing foraging efficiency. Contaminants associated with coal mining (metals, other dissolved solids), domestic sewage (bacteria, nutrients), and agriculture (fertilizers, pesticides, herbicides, and animal waste) cause degradation of water quality and habitats through increased acidity and conductivity, instream oxygen deficiencies, excess nutrification, and excessive algal growths. Furthermore, these threats faced by the Cumberland Darter from sources of sedimentation and contaminants are imminent, the result of ongoing projects that are expected to continue indefinitely. As a result of the imminence of these threats combined with the vulnerability of the remaining small populations to extirpation from natural and manmade threats, we have determined that the present or threatened destruction, modification, or curtailment of the Cumberland Darter habitat and range represents a significant threat of high magnitude. We have no information indicating that the magnitude or imminence of this threat is probably to be appreciably reduced in the foreseeable future.
|Conservation Actions:||This species would benefit from habitat restoration and from improved protection and management of occupied waters.|
|Citation:||NatureServe 2013. Etheostoma susanae. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 October 2014.|
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