|Scientific Name:||Cyprinodon diabolis|
|Species Authority:||Wales, 1930|
|Red List Category & Criteria:||Critically Endangered B1ab(v)+2ab(v); C2a(ii) ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
The Devil's Hole Pupfish is listed as Critically Endangered in view of its extremely small distribution (extent of occurrence and area of occupancy are both less than 1 sq km), occurrence in a single location, and small population size (currently <100 mature individuals) that is continuing to decline. Regular surveys have shown variable population sizes that sometimes have fallen below 50 mature individuals. An apparent increase in population size in 2008 appears to have been a fluctuation. Overall the population has shown a declining trend since the 1990s. Currently the causes of this decline are not fully understood.
|Range Description:||Range is restricted to a single, deep limestone pool at the bottom of Devils Hole, Ash Meadows, Death Valley National Park, Nevada (Lee et al. 1980, Page and Burr 2011). Artificial populations exist elsewhere.|
|Range Map:||Click here to open the map viewer and explore range.|
This species is represented by one natural occurrence. One refugium population and two temporary locations for larval rearing.
Since population surveys began, the wild population has not exceeded 553 individuals. For reasons that are still unclear, the Devils Hole population began to decline in the mid-1990s. By the fall of 2006, an estimated 38 fish remained in the wild, and two refuge populations were lost. In the fall of 2008, the population was estimated at 127 individuals. Source: USFWS, Nevada Fish and Wildlife Office.
The fall 2008 count was estimated at 127 fish; this was the first time triple digits have been estimated since 2004, and the first three-year upward trend since 1996. The average number of pupfish estimated in April 2009 was 70 (note that the spring count is typically and naturally lower than the fall count). This represented a 56% increase over the April 2008 estimate of 45 fish. Source: USFWS, Nevada Fish and Wildlife Office.
More recent surveys, however, are not so optimistic. In September 2012 the population size dropped to around 75 fish, and in the fall of 2013 count the population had declined further to only 65 fish. Source: USFWS, Nevada Fish and Wildlife Office.
|Habitat and Ecology:||Habitat is a deep limestone pool, about 15 meters below the land surface. Water temperature is 32.8 to 33.9 °C, dissolved oxygen 1.8 to 3.3 ppm (Lee et al. 1980). Pupfish rarely leave algae-covered ledge at western end of pool.|
|Use and Trade:||This species is not utilized.|
|Major Threat(s):||This species was formerly threatened by lowered water levels associated with excessive groundwater extraction in the area. Habitat is fenced, and public access is prohibited, but the site remains vulnerable to vandalism (including introduction of non-native aquatic species) and factors that affect water level/quality.|
Stabilization of habitat is the primary recovery goal (see recovery plan, 1980; revised 1990).
In 2006, the USFWS, National Park Service, and Nevada Department of Wildlife launched an emergency effort to reverse the decline of the species. Suspecting that the food source may be a limiting factor, an artificial food was developed and an automatic feeder installed in Devils Hole. Originally a stop-gap measure, this proved to be so successful that it has remained in operation. Another critical decision was to limit access into Devils Hole and not remove pupfish for experimental or captive propagation until the fall population exceeds 200 fish and an increasing population trend is demonstrated for three years. Source: USFWS, Nevada Fish and Wildlife Office.
|Citation:||NatureServe 2014. Cyprinodon diabolis. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 01 July 2015.|
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