Deep in a limestone cave in the arid Northern Mojave Desert lies a fairly small waterhole know as Devils Hole. The water in the hole typically sits between 91.4 to 93.3 degrees Fahrenheit, separated into two distinct areas. One area is a limestone rock shelf, 11 feet 6 inches by 16 feet 5 inches and around 11.8 inches inches deep, while the second area is 11 feet by 55 feet 10 inches. The second area’s depth is unknown but is over 500 feet deep.
The upper 80 feet of the hole is home to the entire population of one of the world’s rarest fish: the Devils Hole pupfish. Averaging about .9 inches long and primarily feeding on algae and small invertebrates, around half of the entire population reside on the limestone shelf section of the pool.
A count of the fish population this past spring revealed the most fish observed during a spring season counts in 25 years, just 191, and a recent survey in September brought the number up to 212. December 5th’s 7.0 magnitude earthquake, which occurred off the coast of Northern California, could have an impact of the critically endangered population.
According to Death Valley National Park, approximately two minutes after the earthquake struck Northern California (around 10:44am), water inside Devils Hole started sloshing, 500 miles away from the earthquake’s epicenter. The waves in the pool, which is almost always still due to the wind shelter created by the collapsed cave surrounding it, reportedly reached around two feet high.
With the waves sweeping over the limestone shelf, most of the organic matter in the shallow area was pushed into the cavern, falling into the well over 500 foot depth below.
“In the short term, this is bad for the pupfish. A lot of pupfish food just sank deeper into the cave, most likely too deep for the fish to get to it. There were likely pupfish eggs on the shelf that were destroyed. But, in the long term, this type of reset is good for the pupfish. It cleaned off any decaying organic matter that could otherwise cause pockets of low oxygen.” – National Park Service biologist Dr. Kevin Wilson.
The pupfish population in Devils Hole has survived several quakes before, recently in 2018, 2019, and 2022. Their reaction typically includes an increase in spawning activity, but Dr. Wilson and other biologists with the National Park Service, U.S. Fish and Wildlife Service, and Nevada Department of Wildlife are evaluating how to mitigate this disruption.