Cyprinodon pecosensis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Cyprinodontiformes Cyprinodontidae

Scientific Name: Cyprinodon pecosensis Echelle & Echelle, 1978
Common Name(s):
English Pecos Pupfish

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2013
Date Assessed: 2011-11-22
Assessor(s): NatureServe
Reviewer(s): Smith, K. & Darwall, W.R.T.
Facilitator/Compiler(s): Hammerson, G.A. & Ormes, M.
This species is listed as Vulnerable because its extent of occurrence appears to be less than 1,000 sq km, area of occupancy is less than 300 sq km, the species occurs in probably fewer than 10 locations, and the species faces ongoing threats and possible declines from introduced fishes and habitat degradation. Trend probably is relatively stable. A decline could put the species in the Endangered category.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species' historical range included the Pecos River system and nearby lakes, sinkholes, and saline springs, from the mouth of Independence Creek, 42 km SE Sheffield, Terrell County, Texas, to Roswell, Chaves County, New Mexico. As of the late 1990s, pure populations occurred in small reaches of the Pecos River and tributaries in Chaves and Eddy counties, New Mexico; in scattered sinkholes, lakes, and saline springs in New Mexico; and in the upper reaches of the Salt Creek drainage, Culberson and Reeves counties, Texas (populations in abandoned gravel pits near Grandfalls, Texas, are hybrid) (USFWS 2000).
Countries occurrence:
United States
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is represented by several unhybridized populations.

Total adult population size is unknown but presumably exceeds 10,000.

This species has been replaced by Cyprinodon pecosensis x C. variegatus hybrids throughout more than two-thirds of historical range (USFWS 1998).

Recent management has stopped the decline and may reverse it (USFWS 2000).
Current Population Trend:Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Habitat includes saline springs, gypsum sinkholes, and desert streams. Sometimes this species occurs in low salinity waters, but it is most typical and abundant in highly saline habitats that support relatively few species. It can survive in water among gravel where there is no surface water (Sublette et al. 1990).

Males establish breeding territories over substrata such as rocky outcrops, mats of submerged vegetation, or scattered rocks and silt; females prefer rock outcrops for spawning (Sublette et al. 1990).
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: This species is of minor value in commercial aquaria.

Threats [top]

Major Threat(s): In the late 1990s, the main threats to the Pecos Pupfish were habitat loss caused by damming and dewatering of the Pecos River, excessive pumping of groundwater, and, since the early 1980s, hybridization with the Sheepshead Minnow (Cyprinodon variegatus). Subsequently, USFWS, BLM, New Mexico Department of Game and Fish, New Mexico Department of Agriculture, New Mexico Division of State Parks, and Texas Parks and Wildlife Department signed a conservation agreement that addressed the significant threats facing this species; the agencies made commitments to protect known extant populations, establish new populations, and prohibit the use of Sheepshead Minnow as bait (Federal Register, 28 December 1998; USFWS 2000).

Introduced Cyprinodon variegatus has negatively impacted the native gene pool of C. pecosensis. Apparently between 1980 and 1984, C. variegatus was introduced into Pecos River in Texas. By 1985, a hybrid swarm of C. pecosensis and C. variegatus occupied roughly one-half of historical range of C. pecosensis (Echelle and Connor 1989). Hybridization with C. variegatus in Red Bluff Reservoir on the Texas-New Mexico line raised concerns that New Mexico populations soon would be jeopardized by hybridization (Sublette et al. 1990). "The early history of the hybrid swarm is explained by genetic swamping, possibly mediated by selection for C. variegatus or C. variegatus x C. pecosensis, at a time when the normally abundant endemic species had been catastrophically depleted" (Childs et al. 1996).

Sinkhole populations are vulnerable to introduction of C. variegatus by anglers. Also, anglers may introduce toxins into sinkholes to eliminate unwanted fishes, including Pecos Pupfish, prior to stocking them with sport fishes.

Populations have been depleted primarily as a result dewatering of habitat due to damming and excessive groundwater pumping, though many forms of habitat degradation have occurred. Lowered water tables have eliminated water flow between sinkholes, isolating these populations. Oil spills from pipelines into Salt Creek, Texas, have occurred and represent an ongoing threat to water quality and pupfish habitat.

River flooding may allow access of exotic fishes to sinkhole habitats. Sinkholes with introduced predatory fishes have smaller populations of Pecos Pupfish than do sinkholes lacking game fish; predation could become a significant threat should the pupfish population continue to decline.

Algal blooms and large-scale fish kills have occurred in the Pecos River, Texas, and may threaten Pecos Pupfish.

Conservation Actions [top]

Conservation Actions: Occurrences need to be protected from Cyprinodon variegatus expansion/introductions and from habitat dewatering.

Citation: NatureServe. 2013. Cyprinodon pecosensis. The IUCN Red List of Threatened Species 2013: e.T6163A15361876. . Downloaded on 18 June 2018.
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