Devils Hole Pupfish

The Devils Hole pupfish (Cyprinodon diabolis) was listed as endangered in 1967. This iridescent blue inch-long fish's only natural habitat is in the 93 degree waters of Devils Hole, located within the Ash Meadows National Wildlife Refuge, Nye County , Nevada, which is a detached unit of Death Valley National Park . Although the cavern is over 400 feet deep, the pupfish are believed to spawn exclusively on a shallow rock shelf just under the waters surface.

This short-lived species (approximately one year) has a natural high and low cycle, with the population in the fall being larger than that in the spring due to natural die-off during the winter months. The population of pupfish has never exceeded 553 individuals since population surveys began in 1972. From the late 1970s through 1996, the population appeared to be relatively stable with an average population size of 324 individuals. In 1997, the fall population surveys started to indicate a downward trend for unknown reasons. The population from 1997 to 2004 declined from an average of 275 individuals to 171 fish. In August and September 2004, two separate rainfall events deposited 1.66 cubic meters of sediment on the main spawning shelf, for a loss of approximately 54 percent of pupfish spawning habitat. Subsequent multi-agency initiated restoration efforts are believed to have restored much of this habitat on the shelf. The population continues to decline for unknown reasons. The adult population count conducted in November 2005 indicated a population of 84 individuals, and an April 2006 population count indicated an adult population of 38 individuals, the lowest count on record.

If you would like additonal information about the Devils Hole pupfish and recovery actions, please contact Bob Williams, Field Supervisor for the Nevada Fish and Wildlife Office. Mr. Williams has been designated the Devils Hole pupfish spokesperson by the Regional Managers involved in the conservation of the species. He can be reached by calling (775) 861-6300.