Warm Springs Pupfish

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Warm Springs Pupfish

Cyprinodon nevadensis pectoralis

ListedOctober 13, 1970
FamilyCyprinodontidae (Killifish)
DescriptionSilvery sided pupfish; males are bright blue.
HabitatThermal springs.
ReproductionSpawns year round.
ThreatsGroundwater pumping.


The warm springs pupfish, Cyprinodon nevadensis pectoralis, the smallest of the four extant sub-species of the Nevada pupfish, ranges from 1.5-2.5 in (3.7-6.2 cm) long. Females and juveniles are silvery; males are bright blue.


Because of its rarity, little is known of the life history of this pupfish. The spawning season runs for most of the year, with a peak from April through June. Like other pupfish, the warm springs sub-species is probably omnivorous, feeding on insects and plant matter.


Although these pupfish reside in the outlet streams of all of their habitat springs, they do not reproduce there. Essential habitat for the warm spring pupfish is the springs' physically stable source pools or headwaters.


The warm springs pupfish has only been found in the Ash Meadows region of Nevada. The species was never very widespread. Today, it is found in Lovell's Spring, sometimes referred to as School's Spring, 0.6 mi (1 km) northwest of Devil's Hole at Ash Meadows (Nye County), Nevada. It is also found in five additional spring flows, all within 0.6 mi (1 km) of Lovell's Spring. The U. S. Fish and Wildlife Service (FWS) estimates that the total warm springs pupfish population is less than 500 fish, with almost half living in School Spring. With the establishment of the Ash Meadows Refuge, four of the six habitats lie on public land withdrawn for wildlife management. Essential habitat for this species includes 2,240 acres (896 hectares) surrounding all of its habitat.


The warm springs pupfish is especially threatened by groundwater pumping that is lowering the water table throughout the region. Because the springs are quite small, they dry quickly when the water level falls. Competition with the introduced mosquitofish could become a problem if they penetrate any further into spring pools. Some predation on the warm springs pupfish is occurring, especially by birds such as the belted kingfisher.

Essential for the continued existence of the warm springs pupfish is protection of its very limited habitat, especially spring water levels. This will involve procuring and enforcing water rights so that spring water levels can be maintained, the control of emergent vegetation around the springs, and the addition of supplemental water whenever necessary.

In 1977 agricultural interests sold about 23 sq mi (60 sq km) of land at Ash meadow to a real estate developer. Attempts by the developer to construct a residential community at Ash Meadow for 55,000 people resulted in widespread land disturbance and water diversions. In May 1982, the FWS used emergency provisions of the Endangered Species Act to invoke protection of several fishes at Ash Meadows. In 1984, after attempts by the FWS to negotiate adequate conservation agreements failed, the developer sold about 11,000 acres (4,450 hectares) to the Nature Conservancy. The property was later purchased by the federal government to establish the Ash Meadows National Wildlife Refuge.

Conservation and Recovery

The FWS published a revised Recovery Plan for the warm springs pupfish in 1990. Much of its remaining critical habitat is protected in the Ash Meadows National Wildlife Refuge. Two additional habitats are privately owned and are potentially threatened by development and other activities. These habitats should be acquired and designated as ecological reserves, or conservation easements negotiated with the private owners. The habitats will also have to be managed to eradicate or reduce the abundance of non-native fish and crayfish. Other necessary actions include monitoring of the abundance of the warm springs pupfish and research into its biology and habitat needs. There should also be a public education campaign to develop a broad base of support for the protection of its rare warm-spring habitats.


U.S. Fish and Wildlife Service
Office of the Regional Director
911 N.E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 321-6118
Fax: (503) 231-2122

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Lloyd 500 Building, Suite 1692
500 N.E. Multnomah Street
Portland, Oregon 97232


Miller, R. R., and J. E. Deacon. 1973. "New Localities of the Rare Warm Springs Pupfish, Cyprinodon nevadensis pectoralis, from Ash Meadows, Nevada." Copeia (1973):137-140.

Soitz, D. L. 1974. "Variation in Life History and Social Organization of Some Populations of Nevada Pupfish, Cyprinodon nevadensis." Ph.D. Dissertation. University of California, Los Angeles.

U.S. Fish and Wildlife Service. 1976. "Warm Springs Pupfish Recovery Plan." U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1990. "Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada." U.S. Fish and Wildlife Service, Portland, Oregon.