Gambusia senilis


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Gambusia senilis
Species Authority: Girard, 1859
Common Name(s):
English Blotched Gambusia
Spanish Guayacon Pinto

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2014
Date Assessed: 2012-02-07
Assessor(s): NatureServe
Reviewer(s): Smith, K. & Darwall, W.R.T.
Facilitator/Compiler(s): Hammerson, G.A. & Ormes, M.
Listed as Near Threatened because extent of occurrence may be less than 20,000 sq km, area of occupancy may be less than 2000 sq km, and habitat quality/quantity and species distribution and abundance probably are declining as a result of ongoing habitat loss/degradation and effects of introduced fish species; however, the rate of decline is unknown, the species occurs in more than 10 locations, and distribution may not be severely fragmented, so the species does not fully meet the criteria for the Vulnerable category.
1994 Rare (Groombridge 1994)
1990 Rare (IUCN 1990)

Geographic Range [top]

Range Description: Range includes the Devils River, Texas (formerly), and Rio Conchos and tributaries, Chihuahua and Durango, Mexico; also the endorheic Rio Sauz basin (Miller 2005, Page and Burr 2011). The species is widely distributed in the Rio Conchos drainage.
Regionally extinct:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by a large number of occurrences in Mexico. The number of locations is uncertain but exceeds 10.

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

Status is unknown, but the species may be secure due to its wide distribution (Minckley et al. 1991). Presumably the trend over the past 10 years or three generations has been relatively stable or declining, but the rate of decline is unknown. Three generations span fewer than 10 years.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Habitat includes stream channels, edges, backwaters; springs, outflows, marshes; eurythermal (Minckley et al. 1991, Page and Burr 2011). Usually this species is collected in quiet, weed-choked surface waters. It is tolerant of wide variations in temperature, chemical conditions, and water flow, and clarity.
Systems: Freshwater

Threats [top]

Major Threat(s): Threats include habitat loss and degradation (e.g., dewatering of habitat) and adverse effects of introduced species (Jelks et al. 2008).

Conservation Actions [top]

Conservation Actions: Better information is needed on current distribution, abundance, threats, and population trend.

Citation: NatureServe 2014. Gambusia senilis. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 27 March 2015.
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