Extremely Rare Fish Discovered in Nevada Cave After Earthquake Reveals Location

by Lauren Boisvert
(Photo by Gina Ferazzi/Los Angeles Times via Getty Images)

The rare Devils Hole pupfish was discovered in momentous numbers after an earthquake in Mexico. The earthquake caused massive waves in the Nevada cave. Biologists counted 263 individual pupfish, the largest amount of these fish found in Devils Hole in almost 20 years.

Devils Hole is a 500-foot-deep watery cave on the side of a cliff in Devils Hole, Nevada. It is also part of Ash Meadows National Wildlife Refuge in Nye County, east of Death Valley National Park. There is a natural aquifer in Ash Meadows, and the water takes 15,000 years to travel from the Nevada Test Site. It goes to the springs at Ash Meadows and into Devils Hole. Ash Meadows is also home to 24 unique plant and animal species that are not found anywhere else but the refuge.

One of those species is the Devils Hole pupfish. The pupfish naturally occurs in Devils Hole and nowhere else. The populations fluctuate based on the season and the amount of seaweed and algae in the cavern. According to the National Park Service, the pupfish are thought to have been isolated for 10,000 to 20,000 years.

In the winter, the population is thought to vary from 100 to 200 individuals. In the summer it boosts to 300 to 500. Recently, though, researchers got a good look at just how many pupfish there are in the Nevada cave. The 7.6 magnitude earthquake in Mexico on Sept. 19 created 4-foot waves in Devils Hole. This stirred up the seaweed and gave scientists a good look at the population from the surface.

Researchers Report Large Number of Naturally Occurring Pupfish in Nevada Cave After Earthquake

Researchers counted 263 pupfish, the largest population since 2003. Then, there were only an estimated 90 pupfish in the Nevada cave. There was also a mysterious decline in pupfish in the mid-1990s, which scientists still haven’t explained. Experts studied water quality and chemistry, pupfish genetics, breeding patterns, and more to try and understand why the populations were declining.

But, what is it about the pupfish that makes it so fascinating? First of all, the water in Devils Hole is a warm, constant 92 degrees. Odd for cave water, which is usually frigid. And strange for a fish species to thrive in. But, according to these recent numbers, the pupfish is indeed thriving.

There’s a shallow part of Devils Hole before a sheer dropoff and the 500-foot cavern, the bottom of which has never been reached. This shallow spot of water is where the pupfish prefer to spend their meals and their mating seasons. Researchers count the pupfish population twice a year in a 2-day process that includes numerous dives and equipment. The smallest count ever recorded was 35 fish, though researchers have tried to breed pupfish in captivity. They even recreate the shallow shelf of Devils Hole. But, there’s just something about this Nevada cave that provides the perfect environment for pupfish breeding.