Death Valley National Park

Death Valley National Park

The mystery of Death Valley's missing pupfish

March 12, 2012, 8:02 am

The Devil's Hole pupfish is arguably one of the cooler species around. These tiny iridescent blue fish, just a bit over an inch long, live in one place only, a deep pool in the Amargosa Valley of west Nevada, in a place called Ash Meadows, an outpost of California's Death Valley National Park. The pool, which is about 8 feet wide and 35 feet long, appears a clear and light blue where a flat rock shelf runs just below its surface, deepening to dark turquoise where the shelf drops off. No one knows how deep the pool is; divers have gone 435 down and not hit bottom. "I like to think of Devil's Hole, when you're looking at it, as a window into the aquifer," says Kevin Wilson, an ecologist and manager of Death Valley's Devil's Hole program.

The water body is not what biologists would consider a welcoming habitat. Its average temperature is 93 degrees, and since it is so still, lacking an outlet where moving water mixes with air, it is oxygen deprived, with about one-third as much oxygen as the average desert spring, says Wilson. Scientists have been keeping watch over these pupfish, one of the most imperiled species in the world, since before the Endangered Species Act was passed. One of the first threats was groundwater pumping from the aquifer feeding the hole in the Amargosa Valley; after a long court battle, the government secured senior water rights protecting the pupfish and their pool in 1976. When the ESA was passed in 1973, pupfish were one of the first species listed.