Pacific Southwest Region
California, Nevada and Klamath Basin

Devils Hole Pupfish 2013 Spring Population Survey

Apr 25, 2013

Dan Balduini (FWS) 702-515-5480,
Cheryl Chipman (NPS) 760-786-3207
Doug Nielsen (NDOW) 702-486-5127 ext.3500

Devils Hole Pupfish 2013 Spring Population Survey

AMARGOSA VALLEY – Devils Hole pupfish counts on April 6-7 of this year indicate the population has declined since the spring of 2012.  Counts this spring estimate 35 observable pupfish.  Spring population survey results are typically 40-60 percent lower than the preceding fall count, which last fall was an estimated 75 fish.

The number of fish is considered to be an index of the number of observable pupfish, based on a methodology that has been in use for 41 years.  This spring’s count represents a decrease from the 63 fish estimated in the spring 2012 population survey. This short lived species (lifespan of approximately one year) experiences a natural high and low cycle, with the population in the fall being greater than that in the spring.

“The continued focus of all the partners will be on the conservation and recovery efforts for the Devils Hole pupfish and its ecosystem,” said Ted Koch, Nevada state supervisor for the U. S. Fish and Wildlife Service.   “Ongoing research regarding this rare fish will assist scientists in understanding food and habitat requirements for their long term survival.”

The reason for the continued decline of Devils Hole pupfish is unclear.  Although the Devils Hole environment is small, changes can be subtle and complex making it difficult to identify specific factors influencing the fish’s population from year to year.  While biologists do not want to speculate about the fish’s population decline, they believe the population may have been influenced to some degree by the effects of three earthquakes and one rain runoff event that took place over the last 14 months.

Managers and biologists from the U. S. Fish and Wildlife Service, National Park Service, and Nevada Department of Wildlife are currently evaluating and developing procedures to implement short and long-term actions for the conservation of the species.  Actions currently being taken to recover the species include supplementing the natural food in Devils Hole and investigating the physical, chemical, and biological factors that contribute to pupfish reproduction and survival.  Additional management actions are under consideration and will be based on the results of these investigations.

Devils Hole pupfish is one of the world’s rarest fishes, spending most of its life in the top 80 feet of the 93 degree waters of cavern in the Mojave Desert, which is managed as part Death Valley National Park in cooperation with the U. S. Fish and Wildlife Service and Nevada Department of Wildlife.  Its habitat is one of the smallest natural ranges known for any vertebrate (fish, amphibian, reptile, bird, or mammal).  Devils Hole has always been an extreme environment, with water temperatures and dissolved oxygen concentrations near their lethal limits for fish.  It is thought this fish has survived and adapted to these harsh conditions for thousands of years.

Earlier this year a hybridized form of Devils Hole pupfish was moved to a new fish conservation facility at Ash Meadows National Wildlife Refuge.   This state-of-the-art facility has been constructed to mimic the harsh conditions of Devils Hole.  The fish, which are thriving in this environment, were moved to aquaria where biologists can conduct important research without disrupting fish in their natural environment.

 - FWS -

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