Death Valley National Park

Death Valley National Park

Species Spotlight: Death Valley Pupfish

January 19, 2010, 11:56 am

by Ashley Pettigrew

In one of the most inhospitable environments in the world it’s well known that animals must adapt to survive. But one species has managed to survive and adapt so well that scientists and researchers now use it to determine the overall health of the ecosystem. Meet the Death Valley pupfish, one of park’s most fascinating creatures.

Only about one inch in size, the endemic Death Valley pupfish makes up for its diminutive size in adaptability. The pupfish survives in solar heated pools found in the Devil’s Hole region of Death Valley National Park. They have been known to survive in water as hot as 112°F (hot tubs max out at around 104°F). Pupfish are so specifically adapted to the heat that when water temperatures drop in the winter, they burrow in to the mud and become dormant. Unlike most other fish, the pupfish can also survive in water two to three times saltier than seawater, a trait attributable to the fact that an inland sea that existed here in the past.

The pupfish, like many inhabitants of the region, are a lesson in evolution. The Devil’s Hole water system is part of a large aquifer hidden beneath the surface of Death Valley National Park. In the thaw that followed the last ice age around 10,000 years ago it left separate pools of lakes and ponds. This separation of populations and species allowed distinct groups of fish, like the pupfish, to develop unique characteristics for survival.

Despite its amazing ability to survive in the harshest environments, the pupfish’s story is not without struggle. In the 1960s, development in the region brought the pupfish to the brink extinction. Because pupfish feed and spawn just below the surface they are highly sensitive to slight decreases in water levels. The pupfish’s habitat was threatened so dramatically, that it was one of the first species to be protected under the Endangered Species Act. Since that time, access to Devil’s Hole has been limited to researchers only.

Today, the pupfish is one of the most extensively researched animals in the park and is generally seen as an indicator of the overall health of the Death Valley ecosystem. Quarterly counts of the fish are conducted and the park has installed monitoring wells to keep a close eye on water levels. In 2006, to the National Park Service implemented additional programs to stabilize and improve the population after a count returned only 38 pupfish, the lowest number ever recorded. These efforts helped the population rebound to almost 100 individuals today. If you’d like to help support Death Valley’s pupfish population, you can make a donation to support Devil’s Hole research through the Death Valley Fund.

Pupfish Fun Facts

  • Pupfish secrete excess salt through their kidneys and gills
  • Pupfish feed on green and brown algae.
  • Pupfish reach full maturity in 2 to 3 months.
  • The average lifespan of a pupfish is 6 to 9 months, although some can survive for over more than one year.
  • Pupfish generally remain dormant through most of the winter, in the spring they spawn and by mid summer many will die from the heat.